Eric J. Simon, Ph.D.

The Role of Episodic Memory in Controlled Evaluative Judgments about Attitudes: An Event-Related Potential Study
Johnson R Jr; Simon EJ; Henkell H; Zhu J
2011 Apr;49(5):945-960, Neuropsychologia
Event-related potentials (ERPs) are unique in their ability to provide information about the timing of activity in the neural networks that perform complex cognitive processes. Given the dearth of extant data from normal controls on the question of whether attitude representations are stored in episodic or semantic memory, the goal here was to study the nature of the memory representations used during conscious attitude evaluations. Thus, we recorded ERPs while participants performed three tasks: attitude evaluations (i.e., agree/disagree), autobiographical cued recall (i.e., You/Not You) and semantic evaluations (i.e., active/inactive). The key finding was that the parietal episodic memory (EM) effect, a well-established correlate of episodic recollection, was elicited by both attitude evaluations and autobiographical retrievals. By contrast, semantic evaluations of the same attitude items elicited less parietal activity, like that elicited by Not You cues, which only access semantic memory. In accord with hemodynamic results, attitude evaluations and autobiographical retrievals also produced overlapping patterns of slow potential (SP) activity from 500 to 900ms preceding the response over left and right inferior frontal, anterior medial frontal and occipital brain areas. Significantly different patterns of SP activity were elicited in these locations for semantic evaluations and Not You cues. Taken together, the results indicate that attitude representations are stored in episodic memory. Retrieval timing varied as a function of task, with earlier retrievals in both evaluation conditions relative to those in the autobiographical condition. The differential roles and timing of memory retrieval in evaluative judgment and memory retrieval tasks are discussed
— id: 121303, year: 2011, vol: 49, page: 945, stat: Journal Article,

The interaction between the mu opioid receptor and filamin a
Simon, Eric J; Onoprishvili, Irma
2010 Dec;35(12):1859-1866, Neurochemical research
Our laboratory embarked on research to discover proteins the interaction of which with the mu opioid receptor (MOPr) is required for its function and regulation. We performed yeast two-hybrid screens, using the carboxy tail of the human MOPr as bait and a human brain library. This yielded a number of proteins that seemed to bind to the MOPr C-tail. The one we chose to study in detail was filamin A (FLNA). Evidence was obtained that there was indeed protein-protein binding between the C-tail of MOPr and FLNA. A human melanoma cell line (M2) lacking the gene for FLNA and a control cell line (A7) which differed from M2 only in having been transfected with the gene for FLNA and expressing the FLNA protein were made available to us. We transfected these cell lines with the gene for MOPr and used them in our studies. The absence of FLNA strongly reduced MOPr downregulation as well as desensitization of adenylyl cyclase inhibition and G protein activation. A recent finding, published here for the first time, is that FLNA is required for the activation by mu opioid agonists of the MAP kinase p38. Deletion studies indicated that the MOPr binding site on FLNA is in the 24th repeat, close to its C-terminal. It was further found that FLNA lacking the N-terminal actin binding domain is as capable as full length FLNA to restore cells to control status, suggesting that actin binding is not required. A surprising finding was that upregulation of MOPr by morphine and some agonist analogs occurs in M2 cells lacking FLNA, whereas normal receptor downregulation takes place in A7 cells
— id: 115420, year: 2010, vol: 35, page: 1859, stat: Journal Article,

The Neurobiology of Addiction: Where We Have Been and Where We Are Going
Koob GF; Simon EJ
2009 Jan;39(1):115-132, Journal of drug issues
A number of dramatic breakthroughs in the neurobiology of addiction have occurred in the past 40 years. Two domains will be highlighted: the neurocircuitry of addiction and the molecular biology of addiction targets. The neurobiological substrates for the reinforcing effects of drugs of abuse have been largely identified both at the initial site of action and in the circuitry involved. In human imaging studies, decreases in dopaminergic function have been identified as a key element of addiction, lending support for research on the role of dopamine in addiction. Three novel areas currently are emerging: the role of deficits in frontal cortex functioning, changes in the brain neurocircuitry that convey long-term vulnerability to relapse, and the role of nondopaminergic systems in the neuroadaptations associated with the development of drug dependence. Parallel to these functional changes have been major advances in our understanding of the molecular biology of addiction; the greatest contribution has been in the understanding of the molecular mechanisms of opioid action. This paper reviews the major developments in our understanding of the molecular biology of the endogenous opioid system and the use of genomics to advance our knowledge of the function and regulation of opioid receptors and endorphins
— id: 138849, year: 2009, vol: 39, page: 115, stat: Journal Article,

MYH9 is a major-effect risk gene for focal segmental glomerulosclerosis
Kopp, Jeffrey B; Smith, Michael W; Nelson, George W; Johnson, Randall C; Freedman, Barry I; Bowden, Donald W; Oleksyk, Taras; McKenzie, Louise M; Kajiyama, Hiroshi; Ahuja, Tejinder S; Berns, Jeffrey S; Briggs, William; Cho, Monique E; Dart, Richard A; Kimmel, Paul L; Korbet, Stephen M; Michel, Donna M; Mokrzycki, Michele H; Schelling, Jeffrey R; Simon, Eric; Trachtman, Howard; Vlahov, David; Winkler, Cheryl A
2008 Oct;40(10):1175-1184, Nature genetics
The increased burden of chronic kidney and end-stage kidney diseases (ESKD) in populations of African ancestry has been largely unexplained. To identify genetic variants predisposing to idiopathic and HIV-1-associated focal segmental glomerulosclerosis (FSGS), we carried out an admixture-mapping linkage-disequilibrium genome scan on 190 African American individuals with FSGS and 222 controls. We identified a chromosome 22 region with a genome-wide logarithm of the odds (lod) score of 9.2 and a peak lod of 12.4 centered on MYH9, a functional candidate gene expressed in kidney podocytes. Multiple MYH9 SNPs and haplotypes were recessively associated with FSGS, most strongly a haplotype spanning exons 14 through 23 (OR = 5.0, 95% CI = 3.5-7.1; P = 4 x 10(-23), n = 852). This association extended to hypertensive ESKD (OR = 2.2, 95% CI = 1.5-3.4; n = 433), but not type 2 diabetic ESKD (n = 476). Genetic variation at the MYH9 locus substantially explains the increased burden of FSGS and hypertensive ESKD among African Americans
— id: 146069, year: 2008, vol: 40, page: 1175, stat: Journal Article,

Filamin A mutant lacking actin-binding domain restores mu opioid receptor regulation in melanoma cells
Onoprishvili, Irma; Ali, Solav; Andria, Matthew L; Shpigel, Adam; Simon, Eric J
2008 Oct;33(10):2054-2061, Neurochemical research
We have previously reported that the protein filamin A (FLA) binds to the carboxyl tail of the mu opioid receptor (MOPr). Using human melanoma cells, which do not express filamin A, we showed that receptor down-regulation, functional desensitization and trafficking are deficient in the absence of FLA (Onoprishvili et al. Mol Pharmacol 64:1092-1100, 2003). Since FLA has a binding domain for actin and is a member of the family of actin cytoskeleton proteins, it is usually assumed that FLA functions via the actin cytoskeleton. We decided to test this hypothesis by preparing cDNA coding for mutant FLA lacking the actin binding domain (FLA-ABD) and expressing FLA-ABD in the human melanoma cell line M2 (M2-ABD cell line). We report here that this mutant is capable of restoring almost as well as full length FLA the down-regulation of the human MOPr. It is similarly very effective in restoring functional desensitization of MOPr, as assessed by the decrease in G-protein activation after chronic exposure of M2-ABD cells to the mu agonist DAMGO. We also found that A7 cells, expressing wild type FLA, exhibit rapid activation of the MAP kinases, ERK 1 and 2, by DAMGO, as shown by a rise in the level of phospho-ERK 1 and 2. This is followed by rapid dephosphorylation (inactivation), which reaches basal level between 30 and 60 min after DAMGO treatment. M2 cells show normal activation of ERK 1 and 2 in the presence of DAMGO, but very slow inactivation. The rapid rate of MAPK inactivation is partially restored by FLA-ABD. We conclude that some functions of FLA do not act via the actin cytoskeleton. It is likely that other functions, not studied here, may require functional binding of the MOPr-FLA complex to actin
— id: 93299, year: 2008, vol: 33, page: 2054, stat: Journal Article,

Essential biology
Campbell, Neil A; Reece, Jane B; Simon, Eric J
San Francisco CA : Pearson/Benjamin Cummings, 2007,
— id: 1765, year: 2007, vol: , page: , stat: ,

Essential biology with physiology
Campbell, Neil A; Reece, Jane B; Simon, Eric J
San Francisco CA : Pearson/Bejamin Cummings, 2007,
— id: 1764, year: 2007, vol: , page: , stat: ,

Chronic morphine treatment up-regulates mu opioid receptor binding in cells lacking filamin A
Onoprishvili, Irma; Simon, Eric J
2007 Oct 26;1177:9-18, Brain research
We investigated the effects of morphine and other agonists on the human mu opioid receptor (MOP) expressed in M2 melanoma cells, lacking the actin cytoskeleton protein filamin A and in A7, a subclone of the M2 melanoma cells, stably transfected with filamin A cDNA. The results of binding experiments showed that after chronic morphine treatment (24 h) of A7 cells, MOP-binding sites were down-regulated to 63% of control, whereas, unexpectedly, in M2 cells, MOP binding was up-regulated to 188% of control naive cells. Similar up-regulation was observed with the agonists methadone and levorphanol. The presence of antagonists (naloxone or CTAP) during chronic morphine treatment inhibited MOP down-regulation in A7 cells. In contrast, morphine-induced up-regulation of MOP in M2 cells was further increased by these antagonists. Chronic morphine desensitized MOP in A7 cells, i.e., it decreased DAMGO-induced stimulation of GTPgammaS binding. In M2 cells DAMGO stimulation of GTPgammaS binding was significantly greater than in A7 cells and was not desensitized by chronic morphine. Pertussis toxin treatment abolished morphine-induced receptor up-regulation in M2 cells, whereas it had no effect on morphine-induced down-regulation in A7 cells. These results indicate that, in the absence of filamin A, chronic treatment with morphine, methadone or levorphanol leads to up-regulation of MOP, to our knowledge, the first instance of opioid receptor up-regulation by agonists in cell culture
— id: 75472, year: 2007, vol: 1177, page: 9, stat: Journal Article,

A member of the heat shock protein 40 family, hlj1, binds to the carboxyl tail of the human mu opioid receptor
Ancevska-Taneva, N; Onoprishvili, I; Andria, M L; Hiller, J M; Simon, E J
2006 Apr 7;1081(1):28-33, Brain research
A yeast two-hybrid screen, using the carboxyl tail of the human mu opioid receptor as bait and a human brain cDNA library as target, indicated that the carboxyl terminal portion of hlj1, a member of the human heat shock protein 40 family, interacts with the carboxyl tail of the human mu opioid receptor. To determine if direct in vitro binding occurs between these two proteins, we performed overlay experiments. Results from the overlay experiments showed that binding occurs between the His fusion protein of hlj1 and the GST fusion protein of the carboxyl tail of the human mu opioid receptor. In contrast, no binding with the His fusion protein of hlj1 occurred with GST alone or the GST fusion protein of the third cytoplasmic loop of the human mu opioid receptor. Results from co-immunoprecipitation studies, carried out in whole HEK cell lysates, confirmed in vivo binding between these two proteins. Immunofluorescent studies, using laser scanning confocal microscopy, showed significant co-localization between hlj1 and the human mu opioid receptor in the cell membrane. The function of this protein-protein interaction and its physiological relevance in animal and human brain is yet to be determined
— id: 63620, year: 2006, vol: 1081, page: 28, stat: Journal Article,

Biology : concepts & connections
Campbell, Neil A; Reece, Jane B; Taylor, Martha R; Simon, Eric J
San Francisco CA : Benjamin Cummings/Pearson, 2006,
— id: 1767, year: 2006, vol: , page: , stat: ,

Opiates: neurobiology
Simon, Eric J
Substance abuse : a comprehensive textbook Philadelphia : Lippincott Williams & Wilkins, 2005,
— id: 5492, year: 2005, vol: , page: ?, stat: Chapter,

Essential biology
Campbell, Neil A; Reece, Jane B; Simon, Eric J
San Francisco CA : Pearson/Benjamin Cummings, 2004,
— id: 1762, year: 2004, vol: , page: , stat: ,

Essential biology with physiology
Campbell, Neil A; Reece, Jane B; Simon, Eric J
San Francisco CA : Pearson/Bejamin Cummings, 2004,
— id: 1761, year: 2004, vol: , page: , stat: ,

Interaction between the mu opioid receptor and filamin A is involved in receptor regulation and trafficking
Onoprishvili, Irma; Andria, Matthew L; Kramer, Hal K; Ancevska-Taneva, Natasa; Hiller, Jacob M; Simon, Eric J
2003 Nov;64(5):1092-1100, Molecular pharmacology
The carboxyl tail of the human mu opioid receptor was shown to bind the carboxyl terminal region of human filamin A, a protein known to couple membrane proteins to actin. Results from yeast two-hybrid screening were confirmed by direct protein-protein binding and by coimmunoprecipitation of filamin and mu opioid receptor from cell lysates. To investigate the role of filamin A in opioid receptor function and regulation, we used the melanoma cell line M2, which does not express filamin A, and its subclone A7, transfected with human filamin A cDNA. Both cell lines were stably transfected with cDNA encoding myc-tagged human mu opioid receptor. Fluorescent studies, using confocal microscopy, provided evidence that filamin and mu opioid receptors were extensively colocalized on the membranes of filamin-expressing melanoma cells. The immunostaining of mu opioid receptors indicated that the lack of filamin had no detectable effect on membrane localization of the receptors. Moreover, mu opioid receptors function normally in the absence of filamin A, as evidenced by studies of opioid binding and DAMGO inhibition of forskolin-stimulated adenylyl cyclase. However, agonist-induced receptor down-regulation and functional desensitization were virtually abolished in cells lacking filamin A. The level of internalized mu-opioid receptors, after 30-min exposure to agonist, was greatly reduced, suggesting a role for filamin in mu opioid receptor trafficking. During these studies, we observed that forskolin activation of adenylyl cyclase was greatly reduced in filamin-lacking cells. An even more unexpected finding was the ability of long-term treatment with [d-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin of M2 cells, containing mu opioid receptors, to restore normal forskolin activation. The mechanism of this effect is currently unknown. It is postulated that the observed effects on mu opioid receptor regulation by filamin A and, by implication, of the actin cytoskeleton may be the result of its role in mu opioid receptor trafficking
— id: 39018, year: 2003, vol: 64, page: 1092, stat: Journal Article,

Identification of a neurorestrictive suppressor element (NRSE) in the human mu-opioid receptor gene (vol 91, pg 73, 2001)
Andria, ML; Simon, EJ
2002 SEP 30 ;105(1-2):161-161, Brain research. Molecular brain research
— id: 33044, year: 2002, vol: 105, page: 161, stat: Journal Article,

Delta opioid activation of the mitogen-activated protein kinase cascade does not require transphosphorylation of receptor tyrosine kinases
Kramer, H Kenneth; Onoprishvili, Irma; Andria, Matthew L; Hanna, Kayane; Sheinkman, Karina; Haddad, Lisa B; Simon, Eric J
2002 ;2:5-5, BMC pharmacology
BACKGROUND: In this study, we investigated the mechanism(s) by which delta opioids induce their potent activation of extracellular signal-regulated protein kinases (ERKs) in different cell lines expressing the cloned delta-opioid receptor (delta-OR). While it has been known for some time that OR stimulation leads to the phosphorylation of both ERK isoforms, the exact progression of events has remained elusive. RESULTS: Our results indicate that the transphosphorylation of an endogenous epidermal growth factor receptor (EGFR) in the human embryonic kidney (HEK-293) cell line does not occur when co-expressed delta-ORs are stimulated by the delta-opioid agonist, D-Ser-Leu-enkephalin-Thr (DSLET). Moreover, neither pre-incubation of cultures with the selective EGFR antagonist, AG1478, nor down-regulation of the EGFR to a point where EGF could no longer activate ERKs had an inhibitory effect on ERK activation by DSLET. These results appear to rule out any structural or catalytic role for the EGFR in the delta-opioid-mediated MAPK cascade. To confirm these results, we used C6 glioma cells, a cell line devoid of the EGFR. In delta-OR-expressing C6 glioma cells, opioids produce a robust phosphorylation of ERK 1 and 2, whereas EGF has no stimulatory effect. Furthermore, antagonists to the RTKs that are endogenously expressed in C6 glioma cells (insulin receptor (IR) and platelet-derived growth factor receptor (PDGFR)) were unable to reduce opioid-mediated ERK activation. CONCLUSION: Taken together, these data suggest that the transactivation of resident RTKs does not appear to be required for OR-mediated ERK phosphorylation and that the tyrosine-phosphorylated delta-OR, itself, is likely to act as its own signalling scaffold
— id: 63621, year: 2002, vol: 2, page: 5, stat: Journal Article,

Identification of a neurorestrictive suppressor element (NRSE) in the human mu-opioid receptor gene
Andria ML; Simon EJ
2001 Jul 13;91(1-2):73-80, Brain research. Molecular brain research
Analysis of the DNA sequence of the human &mgr;-opioid receptor gene (MOR) revealed that a region overlapping the start codon was substantially homologous to a DNA element named the neurorestrictive suppressor element (NRSE) or restrictive element 1 (RE-1). Transient transfection experiments in the L929 and HEK non-neural cell lines showed that expression of a MOR promoter/reporter gene construct was suppressed in non-neural cell lines by inclusion of this MOR NRSE. Expression from a thymidine kinase promoter was also suppressed when the MOR NRSE was inserted upstream or downstream of the reporter gene. The MOR NRSE did not suppress expression of the reporter gene in neural derived cell lines, IMR-32 and Neuro 2a. The transcription factor REST which binds NRSE thereby enacting the suppression of transcription, was encoded in a plasmid and co-transfected into the IMR-32 cells. The REST co-transfected neuronal derived (IMR-32) cells became sensitive to the MOR NRSE mediated suppression of reporter gene expression. Electrophoretic mobility shift experiments revealed that oligonucleotides containing the MOR NRSE were bound by a factor from nuclear extracts of non-neural cell lines, HeLa and Jurkat. This binding was specifically competed by oligonucleotides containing NRSE sequences previously shown to suppress transcription through REST. Thus an NRSE element overlapping the human MOR start codon suppresses gene expression in non-neural cell lines and may help direct neural tissue specific expression of MOR
— id: 21117, year: 2001, vol: 91, page: 73, stat: Journal Article,

Mu-, delta- and kappa-opioid receptor populations are differentially altered in distinct areas of postmortem brains of Alzheimer's disease patients
Mathieu-Kia AM; Fan LQ; Kreek MJ; Simon EJ; Hiller JM
2001 Mar 2;893(1-2):121-134, Brain research
The putative role of the opioid system in cognitive and memory functions prompted us to search for possible changes in the cohort of the major opioid receptors, mu, delta and kappa, in Alzheimer's disease. The present study examines alterations in opioid receptor levels by quantitative autoradiography. These experiments were carried out on coronal sections of postmortem brains from Alzheimer's disease patients and from aged-matched, dementia-free individuals. Brain sections were labeled with the tritiated forms of mu-, delta- and kappa-opioid ligands; DAMGO ([D-Ala(2),N-Me-Phe(4),Gly-ol(5)]-enkephalin), DPDPE ([D-Pen2,5]-enkephalin) and bremazocine (in the presence of mu- and delta-ligands), respectively. Nonspecific binding was determined in the presence of naloxone (10 microM). Brain areas analyzed were caudate, putamen, amygdaloid complex, hippocampal formation and various cerebral and cerebellar cortices. Image analyses of autoradiographs show, that in comparison to the same areas in control brain, statistically significant reductions in mu-opioid receptor binding occur in the subiculum and hippocampus of Alzheimer's disease brains. Binding of delta-opioid receptors is also decreased in the amygdaloid complex and ventral putamen of Alzheimer's disease brains. In contrast, large increases of kappa-opioid receptor binding are found in the dorsal and ventral putamen as well as in the cerebellar cortex of Alzheimer's disease brains. Levels of mu- delta- and kappa-opioid receptor binding are unaltered in the caudate, parahippocampal gyrus and occipito-temporal gyrus. These results may suggest an involvement of the endogenous opioid system in some of the multitude of effects that accompany this dementia
— id: 63622, year: 2001, vol: 893, page: 121, stat: Journal Article,

Tyrosine phosphorylation of the delta-opioid receptor. Evidence for its role in mitogen-activated protein kinase activation and receptor internalization
Kramer HK; Andria ML; Esposito DH; Simon EJ
2000 Sep 15;60(6):781-792, Biochemical pharmacology
The internalization of G-protein-coupled receptors (GPCRs), including the delta opioid receptor (delta-OR), has been shown to involve the phosphorylation of serine and threonine residues. However, recent studies suggest that these residues may not be the only ones phosphorylated in response to prolonged opioid exposure. Tyrosines also appear important for delta-OR signalling, but it remains unclear whether they undergo phosphorylation. We examined whether the delta-OR, stably expressed in Chinese hamster ovary (CHO-K1) cells, was tyrosine-phosphorylated during prolonged agonist treatment. The epitope-tagged delta-OR was purified by immunoprecipitation, and the presence of phosphorylated tyrosines was detected using anti-phosphotyrosine antibodies. Tyrosine residues in the delta-OR were phosphorylated after exposure to the high-affinity agonist [d-Thr(2)]-Leu-enkephalin-Thr (DTLET) in a time- and concentration-dependent manner. Tyrosine phosphorylation of the delta-OR appeared to require the actions of a Src-like protein tyrosine kinase, since the Src inhibitor 4-amino-5-(4-methylphenyl)-7-(t-butyl)-pyrazolo-[3,4-d]-pyrimidine (PP1) attenuated this response. PP1 also attenuated the DTLET-mediated activation of mitogen-activated protein kinase, as well as rapid delta-OR internalization, but not receptor down-regulation. Finally, only opioid agonists that induce receptor internalization via the clathrin-dependent endosomal pathway stimulated significant tyrosine phosphorylation of the delta-OR protein. Evidence is presented that the delta-OR is tyrosine-phosphorylated, and we suggest how this may have an active role in opioid receptor signalling and regulation
— id: 11563, year: 2000, vol: 60, page: 781, stat: Journal Article,

Mutation of tyrosine 318 (Y318F) in the delta-opioid receptor attenuates tyrosine phosphorylation, agonist-dependent receptor internalization, and mitogen-activated protein kinase activation [In Process Citation]
Kramer HK; Andria ML; Kushner SA; Esposito DH; Hiller JM; Simon EJ
2000 Jun 23;79(1-2):55-66, Brain research. Molecular brain research
Opioid receptors are known for their ability to activate diverse second messenger systems. Previously, we showed that selective delta-opioid agonists were able to induce the rapid tyrosine phosphorylation of delta-opioid receptors (delta-ORs) through Src. Src-dependent tyrosine phosphorylation of delta-ORs appears to be important for activation of the mitogen-activated protein kinase cascade and for receptor sequestration into clathrin-coated endosomes, as the Src antagonist, PP1, inhibited both. In an attempt to clarify the role of tyrosine phosphorylation in delta-OR signalling and regulation, we constructed a mutant receptor in which the tyrosine located in the conserved NPXXY motif of the C-terminus was replaced by a phenylalanine (Y318F-delta-OR). Mutation of Y318 resulted in a receptor that was comparable to the wild type in its expression level in HEK-293 cells and in its affinity for opioid ligands. Both receptors showed effective coupling to G proteins and were capable of inhibiting forskolin-stimulated cAMP accumulation with similar potencies. However, the mutant receptor was able to stimulate (35)S-GTPgammaS binding with a lower EC(50) than the wild type receptor. The stimulation of tyrosine phosphorylation in delta-ORs by [D-Thr(2)]-Leu-enkephalin-Thr (DTLET) was significantly less in cells expressing the Y318F-delta-OR than in cells expressing the wild type. In addition, both rapid receptor internalization and down-regulation were markedly attenuated in the mutant. Finally, the mutant receptor was unable to induce a robust activation of the MAPK pathway, suggesting that tyrosine phosphorylation of the delta-OR protein is important for this signalling pathway. These findings implicate tyrosine phosphorylation of Y318 in receptor signalling and agonist-mediated regulation
— id: 11570, year: 2000, vol: 79, page: 55, stat: Journal Article,

mu and delta-opioid receptor agonists induce mitogen-activated protein kinase (MAPK) activation in the absence of receptor internalization
Kramer HK; Simon EJ
2000 Jul 24;39(10):1707-1719, Neuropharmacology
Agonist-promoted internalization (endocytosis) of G-protein-coupled receptors (GPCRs), including all three opioid receptor types (mu, delta and kappa), has been shown to occur via the clathrin endosomal pathway in response to receptor phosphorylation and the actions of the proteins, beta-arrestin and dynamin. Many members of the GPCR family stimulate mitogen-activated protein kinases (MAPK or ERK) activity and, in several cases, it appears that MAPK activation is dependent on receptor internalization. We have reinvestigated the question of whether internalization is obligatory for MAPK activation by opioid receptors, using cell lines expressing the cloned mu or delta receptor. Morphine, which is known to activate both mu and delta receptors, does not induce their rapid internalization into clathrin-coated endosomes. However, morphine produced a robust stimulation of MAPK in both cell lines, as demonstrated by the appearance of phosphorylated MAPK. Moreover, pre-exposure of cells to the internalization inhibitors, concanavalin A or hypertonic sucrose, totally blocked DAMGO mu-selective agonist) and DTLET (delta-selective agonist)-mediated receptor internalization, yet neither treatment affected MAPK phosphorylation induced by these peptides. Our results provide evidence that receptor internalization is not an obligatory requirement for MAPK activation by mu and delta opioid receptors. Hypotheses are presented to explain the seemingly contradictory results obtained from different laboratories
— id: 11613, year: 2000, vol: 39, page: 1707, stat: Journal Article,

POLTERGEIST functions to regulate meristem development downstream of the CLAVATA loci
Yu LP; Simon EJ; Trotochaud AE; Clark SE
2000 Apr;127(8):1661-1670, Development
Mutations at the CLAVATA loci (CLV1, CLV2 and CLV3) result in the accumulation of undifferentiated cells at the shoot and floral meristems. We have isolated three mutant alleles of a novel locus, POLTERGEIST (POL), as suppressors of clv1, clv2 and clv3 phenotypes. All pol mutants were nearly indistinguishable from wild-type plants; however, pol mutations provided recessive, partial suppression of meristem defects in strong clv1 and clv3 mutants, and nearly complete suppression of weak clv1 mutants. pol mutations partially suppressed clv2 floral and pedicel defects in a dominant fashion, and almost completely suppressed clv2 phenotypes in a recessive manner. These observations, along with dominant interactions observed between the pol and wuschel (wus) mutations, indicate that POL functions as a critical regulator of meristem development downstream of the CLV loci and redundantly with WUS. Consistent with this, pol mutations do not suppress clv3 phenotypes by altering CLV1 receptor activation
— id: 63623, year: 2000, vol: 127, page: 1661, stat: Journal Article,

Localization of promoter elements in the human mu-opioid receptor gene and regulation by DNA methylation
Andria ML; Simon EJ
1999 Jun 18;70(1):54-65, Brain research. Molecular brain research
The regulation of mu-opioid receptor gene expression was investigated using several molecular techniques. Genomic clones containing portions of the human mu-opioid receptor gene were sequenced. 5'-RACE analysis of human brain cDNA confirmed the presence of mRNAs up to -313 from the start codon. As was found for the mouse and rat genes, transcription apparently initiates in the absence of a discernable TATA box. To characterize promoter function, portions of the 5'-flanking region were linked to a reporter gene in transient transfection experiments. Two approximately 50 bp adjacent segments had potent, orientation specific promoter activity. More down-stream segments also had promoter activity. None of the 5'-flanking region constructs showed tissue specificity. The potential role of DNA methylation in preventing ectopic expression was investigated by surveying the methylation state of a CpG rich region straddling the start codon. A neural derived cell line (SH-SY5Y) that expresses the mu-opioid receptor lacked virtually any CpG methylation. In contrast, two neural derived cell lines that do not express the mu-opioid receptor were nearly totally methylated while non-neural cell lines had intermediate levels of CpG methylation. Additional transient transfection experiments revealed that CpG methylation of the 5'-flanking region suppressed reporter gene expression. These results indicate that CpG methylation plays an important role in regulating mu-opioid receptor expression in neural cells; however, no association was found with regulation of expression in non-neural cells
— id: 56449, year: 1999, vol: 70, page: 54, stat: Journal Article,

Inactivation of the purified bovine mu opioid receptor by sulfhydryl reagents
Gioannini TL; Onoprishvili I; Hiller JM; Simon EJ
1999 Jan;24(1):37-42, Neurochemical research
We have investigated the role of cysteine residues in a highly purified mu opioid receptor protein (muORP) by examining the effect of -SH reagents on the binding of opioid ligands. Treatment of muORP, which is devoid of additional proteins, eliminates complications that arise from reaction of -SH reagents with other components, such as G proteins. Reagents tested include N-ethylmaleimide, 5,5'-dithiobis(2-nitrobenzoic) acid, and two derivatives of methanethiosulfonate. Specific opioid binding was inactivated by micromolar concentrations of all -SH reagents tested. Agonist binding ([3H]DAMGO) was much more sensitive to inactivation than antagonist binding ([3H]bremazocine). Prebinding muORP with 100 nM naloxone protected antagonist and agonist binding from inactivation by -SH reagents. The results of these experiments strongly suggest that at least one, and possibly more, reactive cysteine residue(s) is present on the mu opioid receptor protein molecule, positioned near the ligand binding site and accessible to -SH reagents
— id: 63624, year: 1999, vol: 24, page: 37, stat: Journal Article,

Role of protein kinase C (PKC) in agonist-induced mu-opioid receptor down-regulation: I. PKC translocation to the membrane of SH-SY5Y neuroblastoma cells is induced by mu-opioid agonists
Kramer HK; Simon EJ
1999 Feb;72(2):585-593, Journal of neurochemistry
Agonist-induced down-regulation of opioid receptors appears to require the phosphorylation of the receptor protein. However, the identities of the specific protein kinases that perform this task remain uncertain. Protein kinase C (PKC) has been shown to catalyze the phosphorylation of several G protein-coupled receptors and potentiate their desensitization toward agonists. However, it is unknown whether opioid receptor agonists induce PKC activation under physiological conditions. Using cultured SH-SY5Y neuroblastoma cells, which naturally express mu- and delta-opioid receptors, we investigated whether mu-opioid receptor agonists can activate PKC by measuring enzyme translocation to the membrane fraction. PKC translocation and opioid receptor densities were simultaneously measured by 3H-phorbol ester and [3H]diprenorphine binding, respectively, to correlate alterations in PKC localization with changes in receptor binding sites. We observed that mu-opioid agonists have a dual effect on membrane PKC density depending on the period of drug exposure. Exposure for 2-6 h to [D-Ala2,N-Me-Phe4,Gly-ol]enkephalin or morphine promotes the translocation of PKC from the cytosol to the plasma membrane. Longer periods of opioid exposure (>12 h) produce a decrease in membrane-bound PKC density to a level well below basal. A significant decrease in [3H]diprenorphine binding sites is first observed at 2 h and continues to decline through the last time point measured (48 h). The opioid receptor antagonist naloxone attenuated both opioid-mediated PKC translocation and receptor down-regulation. These results demonstrate that opioids are capable of activating PKC, as evidenced by enhanced translocation of the enzyme to the cell membrane, and this finding suggests that PKC may have a physiological role in opioid receptor plasticity
— id: 57326, year: 1999, vol: 72, page: 585, stat: Journal Article,

Role of protein kinase C (PKC) in agonist-induced mu-opioid receptor down-regulation: II. Activation and involvement of the alpha, epsilon, and zeta isoforms of PKC
Kramer HK; Simon EJ
1999 Feb;72(2):594-604, Journal of neurochemistry
Phosphorylation of specific amino acid residues is believed to be crucial for the agonist-induced regulation of several G protein-coupled receptors. This is especially true for the three types of opioid receptors (mu, delta, and kappa), which contain consensus sites for phosphorylation by numerous protein kinases. Protein kinase C (PKC) has been shown to catalyze the in vitro phosphorylation of mu- and delta-opioid receptors and to potentiate agonist-induced receptor desensitization. In this series of experiments, we continue our investigation of how opioid-activated PKC contributes to homologous receptor down-regulation and then expand our focus to include the exploration of the mechanism(s) by which mu-opioids produce PKC translocation in SH-SY5Y neuroblastoma cells. [D-Ala2,N-Me-Phe4,Gly-ol]enkephalin (DAMGO)-induced PKC translocation follows a time-dependent and biphasic pattern beginning 2 h after opioid addition, when a pronounced translocation of PKC to the plasma membrane occurs. When opioid exposure is lengthened to >12 h, both cytosolic and particulate PKC levels drop significantly below those of control-treated cells in a process we termed 'reverse translocation.' The opioid receptor antagonist naloxone, the PKC inhibitor chelerythrine, and the L-type calcium channel antagonist nimodipine attenuated opioid-mediated effects on PKC and mu-receptor down-regulation, suggesting that this is a process partially regulated by Ca2+-dependent PKC isoforms. However, chronic exposure to phorbol ester, which depletes the cells of diacylglycerol (DAG) and Ca2+-sensitive PKC isoforms, before DAMGO exposure, had no effect on opioid receptor down-regulation. In addition to expressing conventional (PKC-alpha) and novel (PKC-epsilon) isoforms, SH-SY5Y cells also contain a DAG- and Ca2+-independent, atypical PKC isozyme (PKC-zeta), which does not decrease in expression after prolonged DAMGO or phorbol ester treatment. This led us to investigate whether PKC-zeta is similarly sensitive to activation by mu-opioids. PKC-zeta translocates from the cytosol to the membrane with kinetics similar to those of PKC-alpha and epsilon in response to DAMGO but does not undergo reverse translocation after longer exposure times. Our evidence suggests that direct PKC activation by mu-opioid agonists is involved in the processes that result in mu-receptor down-regulation in human neuroblastoma cells and that conventional, novel, and atypical PKC isozymes are involved
— id: 48732, year: 1999, vol: 72, page: 594, stat: Journal Article,

The bovine mu-opioid receptor: cloning of cDNA and pharmacological characterization of the receptor expressed in mammalian cells
Onoprishvili I; Andria ML; Vilim FS; Hiller JM; Simon EJ
1999 Nov 10;73(1-2):129-137, Brain research. Molecular brain research
The cDNA coding for the bovine mu-opioid receptor has been cloned and sequenced. Conserved sequences from murine delta-receptor cDNA were used as primers in polymerase chain reaction (PCR) to amplify cDNA, prepared by reverse transcription of bovine brain mRNA. This cDNA was used to probe a bovine brain library. The partial sequence obtained was extended to provide the full length clone by PCR. The cDNA has an open reading frame of 1203 base pairs (bp) with a 3'-untranslated region of 1900 bp and a 5'-untranslated region of 265 bp. The protein contains 401 amino acids and has 94% amino acid identity with the human and 91% with the rat mu-opioid receptor. It has the putative seven transmembrane domains, characteristic of G protein-coupled receptors and contains 5 potential N-linked glycosylation sites near the N-terminus. Several potential phosphorylation sites and a putative palmitoylation site are also present. The receptor was stably expressed in HEK293 cells. The binding profile was found to be that of a typical mu receptor, i. e., mu agonists and antagonists, but not delta and kappa ligands, bound with high affinity. Functional assays, namely, opioid stimulation of [35S]GTPgammaS binding and inhibition of forskolin-activated adenylyl cyclase, were also found to be highly specific for mu-opioid agonists. The receptor was downregulated by chronic exposure to mu agonists but not delta or kappa agonists. Evidence is presented indicating that the cloned receptor is the same as the bovine mu receptor previously purified to homogeneity in our laboratory. No evidence was found for genes for multiple mu-type opioid receptors
— id: 11915, year: 1999, vol: 73, page: 129, stat: Journal Article,

Cloning and characterization of a mu opioid receptor from bovine brain
Onoprishvili, I.; Andria, M. L.; Vilim, S. S.; Hiller, J. M.; Carr, K. D.; Simon, E. J.
1999 ;25(1-2):1476-1476, Abstracts (Society for Neuroscience)
— id: 92214, year: 1999, vol: 25, page: 1476, stat: Journal Article,

Functional significance of cysteine residues in the delta opioid receptor studied by site-directed mutagenesis
Ehrlich GK; Andria ML; Zheng X; Kieffer B; Gioannini TL; Hiller JM; Rosenkranz JE; Veksler BM; Zukin RS; Simon EJ
1998 Mar;76(3):269-277, Canadian journal of physiology & pharmacology
Previous work suggested that sulfhydryl groups and disulfide bridges have important functions in opioid binding to the delta opioid receptor. The question regarding which cysteines are essential for ligand binding was approached by replacement of cysteine residues in the cloned delta opioid receptor using site-directed mutagenesis. The wild-type and mutant receptors were expressed stably in Chinese hamster ovary cells. The two extracellular cysteine residues and the six located in transmembrane domains were mutated to serine or alanine, one at a time. Replacement of either of the extracellular cysteines produced a receptor devoid of delta agonist and antagonist binding activity. Immunofluorescence cytochemistry, performed with anti delta opioid receptor antibodies in washed cell monolayers in one of these mutants (Cys-Ser121), and immunoblots, performed on cell extracts, indicate that the receptor was expressed and seems to be associated with the cell membrane. The existence of an essential extracellular disulfide bridge, previously postulated by analogy to other G protein coupled receptors, is strongly supported by our results. Replacement of any one of the six transmembrane cysteines was virtually without effect on the ability of the receptor to bind delta agonists and antagonists. Since there is strong evidence that the transmembrane domains are involved in ligand binding, these results suggest that the cysteine residues, even those near or at the binding site, are not essential for receptor binding. Furthermore, these results support the idea that the striking effects of sulfhydryl reagents on ligand binding of opioid receptors are likely to be due to steric hindrance by the large moieties transferred to the sulfhydryl groups of cysteine residues by these reagents
— id: 57141, year: 1998, vol: 76, page: 269, stat: Journal Article,

Activation of fos in mouse amygdala by local infusion of norepinephrine or atipamezole
Stone EA; Zhang Y; Hiller JM; Simon EJ; Hillman DE
1997 Dec 5;778(1):1-5, Brain research
Norepinephrine (NE) is known to activate a number of immediate-early genes (IEGs) in the brain which may be involved in prolonged changes in neuronal function. To investigate the function of these genes it would be useful to have a model system in which they are induced in specific populations of cells in specific brain regions without systemic drug administration which can affect multiple sites. In the present paper we have shown that local infusions of NE or of the alpha2-adrenoceptor antagonist, atipamezole, in the mouse amygdala produces localized expression of fos. The expression of fos was blocked by a cocktail of an alpha1-(prazosin) and beta1-adrenoceptor (betaxolol) blocker but not by a selective 5-HT1A blocker (WAY100135). Prazosin and betaxolol did not have a nonspecific reducing action on fos expression. It is concluded that localized expression of fos after NE infusion in the mouse amygdala represents a model system for further studies of the role of IEG expression in central noradrenergic function
— id: 7811, year: 1997, vol: 778, page: 1, stat: Journal Article,

A comparison of non-invasive methods of blood pressure measurement in normotensive and hypertensive pregnant women
Arfeen ZU; Maran NJ; Simon EJ; McClure JH
1996 Jul;5(3):168-171, International journal of obstetric anesthesia
We compared two types of automatic non-invasive blood pressure measuring device with sphygmomanometey in 47 normotensive and 38 hypertensive women in the third trimester of pregnancy. An automatic oscillometric device (Accutor) and a volume-clamp device (Finapres) significantly underestimated the diastolic pressure as measured by the fourth Korotkoff sound using a Hawksley random zero sphygmomanometer. The mean difference between the sphygmomanometer and Accutor measurement of diastolic blood pressure was +3.1 mmHg in the normotensive women and +8.3 mmHg in the hypertensive women (P = 0.001). The mean difference between the sphygmomanometer and Finapres measurement of diastolic blood pressure was +6.1 mmHg in the normotensive women and +11.5 mmHg in hypertensive women (P = 0.003). The increased use of continuous non-invasive devices to monitor blood pressure in women with hypertension should be accompanied by sound knowledge of their limitations in this group of patients
— id: 63625, year: 1996, vol: 5, page: 168, stat: Journal Article,

Opioid receptor imaging and displacement studies with [6-O-[11C] methyl]buprenorphine in baboon brain
Galynker, I; Schlyer, D J; Dewey, S L; Fowler, J S; Logan, J; Gatley, S J; MacGregor, R R; Ferrieri, R A; Holland, M J; Brodie, J; Simon, E; Wolf, A P
1996 Apr;23(3):325-331, Nuclear medicine & biology
Buprenorphine (BPN) is a mixed opiate agonist-antagonist used as an analgesic and in the treatment of opiate addiction. We have used [6-O-[11C]methyl]buprenorphine ([11C]BPN) to measure the regional distribution in baboon brain, the test-retest stability of repeated studies in the same animal, the displacement of the labeled drug by naloxone in vivo, and the tissue distribution in mice. The regional distribution of radioactivity in baboon brain determined with PET was striatum > thalamus > cingulate gyrus > frontal cortex > parietal cortex > occipital cortex > cerebellum. This distribution corresponded to opiate receptor density and to previously published data (37). The tracer uptake in adult female baboons showed no significant variation in serial scans in the same baboon with no intervention in the same scanning session. HPLC analysis of baboon plasma showed the presence of labeled metabolites with 92% +/- 2.2% and 43% +/- 14.4% of the intact tracer remaining at 5 and 30 min, respectively. Naloxone, an opiate receptor antagonist, administered 30-40 min after tracer injection at a dose of 1.0 mg/kg i.v., reduced [11C]BPN binding in thalamus, striatum, cingulate gyrus, and frontal cortex to values 0.25 to 0.60 of that with no intervention. There were minimal (< 15%) effects on cerebellum. Naloxone treatment significantly reduced the slope of the Patlak plot in receptor-containing regions. These results demonstrate that [11C]BPN can be displaced by naloxone in vivo, and they affirm the feasibility of using this tracer and displacement methodology for short-term kinetics studies with PET. Mouse tissue distribution data were used to estimate the radiation dosimetry to humans. The critical organ was the small intestine, with a radiation dose estimate to humans of 117 nrad/mCi
— id: 76239, year: 1996, vol: 23, page: 325, stat: Journal Article,

Autoradiographic comparison of [3H]DPDPE and [3H]DSLET binding: evidence for distinct delta 1 and delta 2 opioid receptor populations in rat brain
Hiller JM; Fan LQ; Simon EJ
1996 May 6;719(1-2):85-95, Brain research
The delta opioid ligands, [3H]DPDPE (delta 1) and [3H]DSLET (delta 2) were used in quantitative autoradiographic experiments to ascertain whether separate populations of delta opioid subtypes could be identified in rat brain. Densitometric image analysis showed a general similarity in delta 1 and delta 2 distributions. However, statistically significant differences in binding levels were observed in anatomically discrete regions. Examples of these regions and their delta 2/delta 1 ratio(s) are: dorsomedial hypothalamus (9.3), ventromedial hypothalamus (4.9), superior colliculis (2.7), medial division of bed nucleus stria terminalis (1.6-3.0), external cortex of the inferior colliculis (2.1), amygdaloid nuclei (1.5-2.1), cingulate cortex (1.8), CA1, CA2, and CA3 regions of Ammon's horn (1.6-2.0), dentate gyrus (1.7), laminar VI of the frontal, forelimb, hindlimb and parietal cortices (1.3-1.8), nucleus accumbens (1.4) and caudate/putamen (1.3). These findings provide evidence supporting the existence of distinct delta 1 and delta 2 opioid receptors
— id: 57419, year: 1996, vol: 719, page: 85, stat: Journal Article,

Chronic food restriction alters mu and kappa opioid receptor binding in the parabrachial nucleus of the rat: a quantitative autoradiographic study
Wolinsky TD; Carr KD; Hiller JM; Simon EJ
1996 Jan 15;706(2):333-336, Brain research
Using quantitative autoradiography, it was previously observed that chronic food restriction alters mu and kappa receptor binding in several regions of the rat forebrain. The present autoradiographic study was designed to investigate whether food restriction affects regional mu and kappa binding in the brainstem. [3H]DAGO (mu) and-mu/delta blocked [3H]BMZ (kappa) binding were analyzed in 21 brainstem regions. A significant decrease in mu binding was observed in the external lateral and external medial subnuclei of the parabrachial nucleus while a significant increase in kappa binding was observed in the external lateral subnucleus. The possible functional significance of these changes is discussed
— id: 8089, year: 1996, vol: 706, page: 333, stat: Journal Article,

Secondary transfer of patients with fulminant hepatic failure
Dryden CM; Simon EJ
1995 Feb 1-14;53(3):70-73, British journal of hospital medicine
The principles of stabilisation before and monitoring during transportation are well established in intensive care practice, but fulminant hepatic failure presents especial problems. Transfer of patients to specialist liver failure units needs to be carried out without interruption of therapy aimed at delaying the onset of cerebral oedema, sepsis and haemodynamic instability
— id: 63627, year: 1995, vol: 53, page: 70, stat: Journal Article,

Functional reconstitution of a highly purified mu-opioid receptor protein with purified G proteins in liposomes
Fan LQ; Gioannini TL; Wolinsky T; Hiller JM; Simon EJ
1995 Dec;65(6):2537-2542, Journal of neurochemistry
A mu-opioid receptor protein (mu-ORP) purified to homogeneity from bovine striatal membranes has been functionally reconstituted in liposomes with highly purified heterotrimeric guanine nucleotide regulatory proteins (G proteins). A mixture of bovine brain G proteins, predominantly GoA, was used for most of the experiments, but some experiments were performed with individual pure G proteins, GoA, GoB, Gi1, and Gi2. Low Km GTPase was stimulated up to 150% by mu-opioid receptor agonists when both mu-ORP and a G protein (either the brain G protein mixture or a single heterotrimeric G protein) were present in the liposomes. Stimulation by a selective mu-agonist was concentration dependent and was reversed by the antagonist (-)-naloxone, but not by its inactive enantiomer, (+)-naloxone. The mu selectivity of mu-ORP was demonstrated by the inability of delta and kappa agonists to stimulate GTPase in this system. High-affinity mu-agonist binding was also restored by reconstitution with the brain G protein mixture and with each of the four pure Gi and G(o) proteins studied. The binding of mu agonists is sensitive to inhibition by GTP gamma S and by sodium
— id: 56812, year: 1995, vol: 65, page: 2537, stat: Journal Article,

Structural model for the beta-amyloid fibril based on interstrand alignment of an antiparallel-sheet comprising a C-terminal peptide
Lansbury PT Jr; Costa PR; Griffiths JM; Simon EJ; Auger M; Halverson KJ; Kocisko DA; Hendsch ZS; Ashburn TT; Spencer RG; et al.
1995 Nov;2(11):990-998, Nature structural biology
Amyloids are a class of noncrystalline, yet ordered, protein aggregates. A new approach was used to provide the initial structural data on an amyloid fibril--comprising a peptide (beta 34-42) from the C-terminus of the beta-amyloid protein--based on measurement of intramolecular 13C-13C distances and 13C chemical shifts by solid-state 13C NMR and individual amide absorption frequencies by isotope-edited infrared spectroscopy. Intermolecular orientation and alignment within the amyloid sheet was determined by fitting models to observed intermolecular 13C-13C couplings. Although the structural model we present is defined to relatively low resolution, it nevertheless shows a pleated antiparallel beta-sheet characterized by a specific intermolecular alignment
— id: 63626, year: 1995, vol: 2, page: 990, stat: Journal Article,

Historical summary of NIDA supported opioid research: A tribute to NIDA on its 20th anniversary
Simon EJ
1995 ;152:42-44, NIDA research monograph series
— id: 8116, year: 1995, vol: 152, page: 42, stat: Journal Article,

Recent studies on a mu-opioid receptor purified from bovine striatum
Simon EJ
1995 May 10;757:324-331, Annals of the New York Academy of Sciences
— id: 56789, year: 1995, vol: 757, page: 324, stat: Journal Article,

Molecular characterization of human mu-opioid receptor gene: Demonstration of promoter activity
Andria ML; Ehrlich GK; Simon EJ
1994 ;54(1):9-10, Regulatory peptides
— id: 8099, year: 1994, vol: 54, page: 9, stat: Journal Article,

RECONSTITUTION IN LIPOSOMES OF A MU-OPIOID BINDING-PROTEIN PURIFIED TO HOMOGENEITY FROM BOVINE STRIATAL MEMBRANES
GIOANNINI, TL; FAN, LQ; HYDE, L; OFRI, D; HILLER, JM; SIMON, EJ
1994 FEB 21 ;78(2):S55-S56, Regulatory peptides
An opioid binding protein (OBP) purified to homogeneity from bovine striatal membranes was reconstituted into liposomes. For most experiments a CHAPS extract of bovine striatum, devoid of opioid binding, served as source of G-proteins and lipids. Liposomes were formed by precipitation of a mixture of OBP and CHAPS extract with polyethylene glycol-6000 (PEG). Reconstituted OBP bound mu agonist ligands stereospecifically and with high affinity, similar to that of membrane-bound mu-receptors. The binding was highly selective for mu-ligands, as compared to delta and kappa-ligands and was completely inhibited by GTP gamma S. Similar results were obtained in reconstitution experiments with purified G-proteins. Stimulation of low Km GTPase by mu-agonists was observed. These results indicate that recoupling of purified receptor with G protein has taken place in this system and confirm that OBP is a mu binding protein
— id: 52527, year: 1994, vol: 78, page: S55, stat: Journal Article,

Immunohistochemical localization of mu-opioid receptors in rat brain using antibodies generated against a peptide sequence present in a purified mu-opioid binding protein
Hiller JM; Zhang Y; Bing G; Gioannini TL; Stone EA; Simon EJ
1994 Oct;62(3):829-841, Neuroscience
Light-microscope visualization in rat brain of a pattern of distribution of immunoreactivity, which included immunolabeled perikarya and beaded processes, was achieved using an immunoaffinity purified polyclonal antibody, Ab165, which recognizes the amino acid sequence, IRNLRQDRSKYY, found in the mu-opioid binding protein purified in our laboratory. Immunohistochemical staining with Ab165 was carried out by the avidin-biotin procedure. Antibody, preabsorbed with antigen, served as control. Extensive immunoreactivity was seen in the hippocampal formation, the amygdaloid complex, the striatal complex, cortical regions, select areas of the thalamus and hypothalamus and in laminae I and II of the dorsal horn in spinal cord. The distribution of immunoreactivity in the rat brain of antibody 165, which recognizes a purified mu-opioid binding protein, is concordant with the distribution of mu-opioid binding sites as determined by other laboratories in autoradiographic, electrophysiological and immunocytochemical studies. These findings have enabled us to distinguish areas possessing large fields of mu-opioid receptor containing cell bodies from areas possessing dense networks of immunolabeled neuronal processes or mixtures of both
— id: 56651, year: 1994, vol: 62, page: 829, stat: Journal Article,

Antinociception following subarachnoid bestatin in rats
Wang BC; Li D; Hiller JM; Simon EJ; Turndorf H
1994 ;19:2S66-2S66, Regional anesthesia
— id: 47287, year: 1994, vol: 19, page: 2S66, stat: Journal Article,

Effects of chronic food restriction on mu and kappa opioid binding in rat forebrain: a quantitative autoradiographic study
Wolinsky TD; Carr KD; Hiller JM; Simon EJ
1994 Sep 12;656(2):274-280, Brain research
It was previously observed that chronic food restriction lowers the threshold for lateral hypothalamic self-stimulation in a manner that is reversible by mu- and kappa-selective opioid antagonists. The present quantitative autoradiographic study was designed to investigate whether chronic food restriction alters regional mu and kappa opioid binding in brain. [3H]DAGO (mu) and mu/delta blocked [3H]BMZ (kappa) binding were analyzed in 34 brain regions from the medial prefrontal cortex to posterior hypothalamus. Significant reductions in mu binding were observed in caudal portions of the medial and lateral habenula, and the basolateral and basomedial nuclei of the amygdala. kappa binding was similarly reduced in medial habenula. Large increases in kappa binding were observed in the bed nucleus of the stria terminalis, ventral pallidum, and medial preoptic area. The possible involvement of these changes in the sensitization of reward by food restriction is discussed
— id: 6781, year: 1994, vol: 656, page: 274, stat: Journal Article,

Effect of chronic food restriction on regional Kappa opioid receptor binding in the rat: A quantitative autoradiographic study
Wolinsky, T. D.; Carr, K. D.; Hiller, J. M.; Simon, E. J.
1994 ;20(1-2):752-752, Abstracts (Society for Neuroscience)
— id: 92221, year: 1994, vol: 20, page: 752, stat: Journal Article,

Opioids II
Adler, Martin W; Herz, Albert; Akil, H; Simon, Eric J
Berlin : Springer Verlag, 1993,
— id: 1766, year: 1993, vol: , page: , stat: ,

Opioids
Akil, H; Herz, Albert; Simon, Eric J
Berlin : Springer Verlag, 1993,
— id: 1760, year: 1993, vol: , page: , stat: ,

Reconstitution of a purified mu-opioid binding protein in liposomes: selective, high affinity, GTP gamma S-sensitive mu-opioid agonist binding is restored
Gioannini TL; Fan LQ; Hyde L; Ofri D; Yao YH; Hiller JM; Simon EJ
1993 Jul 30;194(2):901-908, Biochemical & biophysical research communications
An opioid binding protein (OBP) purified to homogeneity from bovine striatal membranes has been reconstituted in liposomes. The liposomes were produced by PEG-precipitation of OBP in the presence of a CHAPS extract of bovine striatum, devoid of opioid binding. High affinity mu-agonist binding was restored. The binding was selective for mu-agonists, stereospecific and inhibited by GTP gamma S. These results demonstrate that there is recoupling of OBP with G-protein and confirm our earlier evidence that the purified OBP is a mu-opioid binding site
— id: 42058, year: 1993, vol: 194, page: 901, stat: Journal Article,

Antisera against peptides derived from a purified mu-opioid binding protein recognize the protein as well as mu-opioid receptors in brain regions and a cell line
Gioannini TL; Yao YH; Hiller JM; Taylor LP; Simon EJ
1993 Oct;44(4):796-801, Molecular pharmacology
Two peptides, which have no significant homology with known protein structures, were obtained by microsequencing of a mu-opioid binding protein purified to homogeneity from bovine striatal membranes. Polyclonal antibodies generated against portions of these peptides immunoprecipitated up to 65% of radiolabeled purified opioid binding protein. Sequential immunoprecipitations, using antibodies directed against portions of the two different peptides, confirmed that the peptides are derived from the same protein. Immunoblots of the protein with antipeptide antibodies revealed a protein band corresponding to the molecular weight of denatured reduced mu-opioid binding protein. The immunoresponse was blocked by the appropriate peptide and was not observed with irrelevant antisera. The antipeptide antibodies were used for immunoblots of sodium dodecyl sulfate extracts of tissues from bovine brain regions and of the mu receptor-containing cell line SK-N-SH. Affinity-purified antipeptide antibody detected an immunoreactive protein of molecular weight 65,000 in brain regions containing high levels of mu-opioid receptors (striatum, thalamus, hippocampus, and frontal cortex) and in the cell line SK-N-SH. Pons, which contains low levels of receptors, produced a a barely detectable signal, whereas white matter, HeLa cells, and C6 glioma cells, devoid of opioid binding activity, produced no detectable signal. The correlation between immunoreactivity and the presence of mu-opioid binding in brain regions and cell lines and the correspondence of the molecular weight of the immunoreactive protein to that of mu-opioid receptors provide strong evidence that the peptide antisera recognize mu receptors
— id: 56531, year: 1993, vol: 44, page: 796, stat: Journal Article,

Alterations in delta opioid receptor levels in discrete areas of the neocortex and in the globus pallidus of the aging guinea pig: a quantitative autoradiographic study
Hiller JM; Fan LQ; Simon EJ
1993 Jun 18;614(1-2):86-98, Brain research
The effect of aging on delta opioid receptors was examined in the brains of guinea pigs aged 1, 6, 24 and 36 months. Quantitative autoradiography was used to monitor the concentrations of delta receptors in various anatomical regions at five rostro-caudal levels. delta opioid receptor populations were found to be remarkably stable throughout the life span of this species. We have, however, discovered anatomical areas which offer striking exceptions. In the globus pallidus, progressive age-related losses of delta receptors reached 50% in the senescent animal. In contrast, laminae I, II of the lateral agranular frontal cortex and laminae I, II and III, IV of the primary somatosensory cortex demonstrated age-related increases in the concentrations of delta receptors ranging from 30 to 45%. These changes are discussed with the view to their being functionally related components of motor circuitry involving pyramidal and extrapyramidal elements
— id: 57304, year: 1993, vol: 614, page: 86, stat: Journal Article,

Immunohistochemical localization of mu opioid receptors in rat brain with antibodies against a peptide sequence derived from a purified opioid binding protein (OBP)
Hiller, J. M.; Bing, G.; Stone, E.; Gioannini, T. L.; Simon, E. J.
1993 ;19(1-3):74-74, Abstracts (Society for Neuroscience)
— id: 92502, year: 1993, vol: 19, page: 74, stat: Journal Article,

Evaluation of three portable suction devices
Simon EJ; Davidson JA; Boom SJ
1993 Sep;48(9):807-809, Anaesthesia
Three portable suction devices were evaluated and compared with a wall-mounted vacuum driven suction unit. The Repro-med Res-Q-Vac, the Drager Sujector 2000 and the Laerdal suction unit were assessed by measuring the time taken to aspirate 140 ml of mock gastric contents. The respective times for each device, expressed as mean and (range) were 7.39 (4.3-10.4), 8.6 (7.8-9.4) and 11.4 (9.4-12.6) s. These compare favourable with the Ohmeda suction unit (7.27 (6.2-8.9)). Each type of device has advantages and disadvantages when factors such as size, power supply and portability are considered, and each will be the most suitable for a particular situation
— id: 63628, year: 1993, vol: 48, page: 807, stat: Journal Article,

Photoaffinity ligands for the mu opioid receptor
Simon EJ; Fan LQ; Hiller JM; Seyed-Mozaffari A; Schultz AG; Archer S
1993 ;53(14):1173-1178, Life sciences
Two affinity ligands, 6 beta-(5-Azido-2-nitrophenacetamido) 14 beta-hydroxy-7,8-dihydromorphinone (4) and 6 beta-(5-azido-2-nitrophenacetamido) 14 beta-hydroxy-7,8-dihydro-N- cyclopropylmethylnormorphinone (5) bind reversibly to opioid receptors present in bovine caudate membranes and photolyse in a range of wavelengths centered about 366 nm to produce wash-resistant binding to the mu receptor. At these wavelengths very little if any photodestruction of the mu receptor occurs over the 20 minute period of irradiation at 0 degree C
— id: 13314, year: 1993, vol: 53, page: 1173, stat: Journal Article,

The effect of chronic food restriction on mu opioid receptors in the rat: A quantitative autoradiographic study
Wolinsky, T. D.; Carr, K.; Hiller, J. M.; Simon, E. J.
1993 ;19(1-3):1154-1154, Abstracts (Society for Neuroscience)
— id: 92224, year: 1993, vol: 19, page: 1154, stat: Journal Article,

Immunoblots with rhodopsin antisera suggest that a purified mu opioid binding protein has structural characteristics of a G-protein-coupled receptor
Gioannini TL; Weiss ER; Johnson GL; Hiller JM; Simon EJ
1992 Jan 1;89(1):52-55, Proceedings of the National Academy of Sciences of the United States of America
A mu opioid binding protein (OBP), previously purified to homogeneity from bovine striatal membranes, was examined by immunoblotting with six antisera against bovine rhodopsin. An antibody against the carboxyl-terminal tail of rhodopsin and one against membrane-associated rhodopsin gave strong signals at the appropriate molecular mass (65 kDa). An antibody directed against the first cytoplasmic loop of rhodopsin was weakly reactive. Three other antibodies did not recognize OBP. This pattern of crossreactivity was identical to that previously seen with beta-adrenergic receptors. The existence of domains in the OBP, which are antigenically similar to those in two other guanine nucleotide regulatory protein-coupled receptors, supports the hypothesis that mu opioid receptors have the structure characteristic of this receptor family
— id: 13801, year: 1992, vol: 89, page: 52, stat: Journal Article,

Recent studies on a mu opioid binding protein purified from bovine striatal membranes
Gioannini TL; Yao YH; Hiller JM; Simon EJ
1992 ;119:34-38, NIDA research monograph series
— id: 13796, year: 1992, vol: 119, page: 34, stat: Journal Article,

Age-related changes in kappa opioid receptors in the guinea-pig brain: a quantitative autoradiographic study
Hiller JM; Fan LQ; Simon EJ
1992 Oct;50(3):663-673, Neuroscience
Investigation into the effect of aging on kappa opioid receptors in the brains of guinea-pigs was carried out in animals aged one, six, 24 and 36 months. Quantitative autoradiography was used to monitor the concentration of kappa receptors in various anatomic regions at five rostrocaudal levels in each age-group. Areas of high binding were found in the deep layers (laminae V, VI) of the neocortex and in the internal band of the periallocortical, dorsal agranular insular cortex. Among non-cortical areas examined, the nucleus accumbens and the substantia nigra possessed kappa binding levels equal to those seen in the deep neocortical layers. In all cases where an age-related change in the level of kappa receptors was detected, the direction of the change was one of decreased binding with advancing age. Statistical analysis of the binding data revealed that the one-month-old animal possessed the highest levels of kappa binding among all age groups examined. The vast majority of age-related changes in kappa binding levels occurred in laminae V and VI of neocortical regions. The per cent decreases (18-42%), as well as their age of onset (six to 36 months) varied in different anatomical regions. Possible mechanisms to explain the age-related decreases in kappa opioid binding are presented. The majority of the age-related decreases in kappa opioid binding are found in areas of the neocortex which are characterized by their motor, sensory and associative functions. It is within these three areas of function that diminutions in performance are most apparent in senescence
— id: 57443, year: 1992, vol: 50, page: 663, stat: Journal Article,

Chimeric enkephalin-cystatins: opioid binding and structure-activity relationships of inhibitory domains
Marks N; Berg MJ; Makofske RC; Swistok J; Simon EJ; Ofri D; Del Compare K; Danho W
1992 Jul-Aug;5(4):194-200, Peptide research
A chimeric inhibitor of cysteine proteinases, YGGFLQVVAGK.amide, was synthesized for use in examining SAR of its cystatin and opioid domains. Analogs were prepared by solid-phase syntheses and evaluated for inhibition of rat brain cathepsin L (E.C. 3.4.22.15) and papain (E.C.3.4.22.2), or binding to rat brain opioid receptors using tritiated DSLET (delta), DAGO (mu) and U69593 (kappa) in competitive binding assays. Cystatin consensus analogs QVVAGK- or N-Ac.QVVK.amide were weakly active as inhibitors, but were enhanced 10-fold to 20-fold with N-terminal L-, FL-, GFL-, GGFL-, or YGGFL, yielding Ki 3 microM and 26 microM for cathepsin L and papain, respectively. YGGFL itself was inactive, but expressed inhibition with N-terminal Q-, QV-, QVV-, etc. Highest activity was found with YGGFLQVK.amide (Ki, 2 microM). N-Dns analogs differentially increased inhibition for papain, whereas an N-Ac-cyclic peptide, N-Ac-CKYGGFLQVVKC.amide, was 2-fold to 10-fold less potent than the two-domain inhibitor. Chimeric peptides containing YGGFL were equipotent as delta-ligands (Ki, 1.7-3.7 nM), but were 2-fold to 10-fold more potent as mu ligands (3.7-11 nM) versus YGGFL itself (37 nM). Two analogs with -QVVAK- and -QVK.amide expressed kappa-binding properties. These data demonstrate the feasibility of using chimeric peptides as probes for exploring enzyme catalysis, and the potential for targeting inhibitors to endosomal or lysosomal compartments via receptor-mediated uptake in cells
— id: 42059, year: 1992, vol: 5, page: 194, stat: Journal Article,

Lesioning of the nucleus basalis of Meynert has differential effects on mu, delta and kappa opioid receptor binding in rat brain: a quantitative autoradiographic study
Ofri D; Fan LQ; Simon EJ; Hiller JM
1992 May 29;581(2):252-260, Brain research
Opioid receptor binding was investigated in rat brain following lesioning of the nucleus basalis of Meynert (nbM). The nbM, which provides cholinergic input to the cortex, was lesioned unilaterally using ibotenic acid. The efficacy of lesioning was confirmed by the observation of a significant decrease in choline acetyltransferase (ChAT) activity in the ipsilateral prefrontal cortex. The specific laminar and regional distribution of mu, delta and kappa opioid receptor binding was quantitated in various cortical and limbic structures in the rat using autoradiography. Distinct medial to lateral gradients of mu and kappa opioid binding were observed in regions of the cerebral cortex. In the lesioned hemisphere the levels of mu, delta and kappa opioid binding were altered in localized areas of the cerebral cortex and the hippocampus. The direction of these binding changes varied with the opioid receptor type being assessed. Delta opioid binding was increased in the lateral portions of the frontal, occipital, perirhinal and retrosplenial granular cortices. Kappa opioid binding was increased in the lateral portion of the occipital cortex and in the CA3 region of the hippocampus. In contrast, mu opioid binding was decreased in the lateral portions of the frontal, entorhinal and forelimb cortices. These opioid receptor changes are discussed with respect to the interactions between the cholinergic and opioid systems, and relevance of the nbM lesion model to Alzheimer's disease
— id: 13592, year: 1992, vol: 581, page: 252, stat: Journal Article,

Characterization of solubilized opioid receptors: reconstitution and uncoupling of guanine nucleotide-sensitive agonist binding
Ofri D; Ritter AM; Liu YF; Gioannini TL; Hiller JM; Simon EJ
1992 Feb;58(2):628-635, Journal of neurochemistry
Opioid receptors were solubilized from bovine striatal membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate-(CHAPS). High concentrations of NaCl (0.5-1.0 M) were necessary to ensure optimal yields, which ranged from 40 to 50% of membrane-bound receptors. This requirement was found to be specific for sodium, with only lithium able to substitute partially, as previously reported for solubilization with digitonin. Opioid antagonists, but not agonists, were able to bind to soluble receptors with high affinity. High-affinity binding of mu, delta, and kappa agonists was reconstituted following polyethylene glycol precipitation and resuspension of CHAPS extract. Evidence is presented suggesting that this is the result of inclusion of receptors in liposomes. Competition and saturation studies indicate that the three opioid receptor types retain their selectivity and that they exist in the reconstituted CHAPS extract in a ratio (50:15:35) identical to that in the membranes. In reconstituted CHAPS extract, as in membranes, mu-agonist binding was found to be coupled to a guanine nucleotide binding protein (G protein), as demonstrated by the sensitivity of [3H][D-Ala2,N-methyl-Phe4,Gly5-ol]-enkephalin ([3H]DAGO) binding to guanosine 5'-O-(thiotriphosphate) (GTP gamma S). In the reconstituted CHAPS extract, complete and irreversible uncoupling by GTP gamma S was observed, whereas membrane-bound receptors were uncoupled only partially. Treatment with GTP gamma S, at concentrations that uncoupled the mu receptors almost completely, resulted in a fourfold decrease in the Bmax of [3H]DAGO binding with a relatively small change in the KD. Competition experiments showed that the Ki of DAGO against [3H]bremazocine was increased 200-fold.(ABSTRACT TRUNCATED AT 250 WORDS)
— id: 13710, year: 1992, vol: 58, page: 628, stat: Journal Article,

Sulfhydryl groups on opioid receptors revisited. Evidence for two sulfhydryl groups at or near the active site of the mu opioid receptor
Ofri D; Simon EJ
1992 Summer;2(2):109-119, Receptor
Sulfhydryl groups were studied in opioid receptors solubilized from bovine striatal membranes and reconstituted into liposomes. This system has the advantage of permitting the complete uncoupling of tightly coupled opioid binding sites from guanine nucleotide binding proteins. Sensitivity of opioid receptors to N-ethylmaleimide (NEM) inactivation, as measured by [3H]bremazocine binding, was similar whether coupled or uncoupled from the G protein. Moreover, the binding of uncoupled receptors could be protected from NEM inactivation by preincubation with a ligand, as previously observed in coupled, membrane-bound receptors. These findings provide strong support of earlier results suggesting the presence of sulfhydryl groups on opioid binding sites. An examination of the major receptor types provided the following decreasing order of sensitivity to NEM: mu > delta > kappa. Mu agonist binding was found to be much more sensitive to NEM than antagonist binding, especially in the presence of NaCl, which affects the binding of the two types of ligands in opposite directions, as previously reported for membrane-bound receptors. At 100 microM NEM in the presence of 100 mM NaCl, [3H] (D-Ala2,N-methyl-Phe4,Gly-ol)-enkephalin (DAGO) binding is essentially eliminated, whereas [3H]bremazocine or [3H]naloxone binding is virtually unaffected. These results are most readily explained by the hypothesis that there are two sulfhydryl groups at or near the mu binding site; one essential for agonist (but not antagonist) binding, the other essential for antagonist and perhaps, also agonist binding. The sodium effect on NEM inactivation of antagonist binding was maintained in the uncoupled state indicating that this effect occurs at the level of the receptor protein
— id: 13795, year: 1992, vol: 2, page: 109, stat: Journal Article,

Opioid receptors and their biochemistry
Simon EJ; Gioannini TL; Yao YH; Hiller JM
1992 ;15 Suppl 1 Pt A:48A-49A, Clinical neuropharmacology
— id: 13797, year: 1992, vol: 15 Suppl 1 Pt A, page: 48A, stat: Journal Article,

Studies on mu-opioid-binding sites with peptide antibodies
Simon EJ; Gioannini TL; Yao YH; Hiller JM
1992 ;126:57-65, NIDA research monograph series
— id: 13793, year: 1992, vol: 126, page: 57, stat: Journal Article,

Effects of stress on opioid receptor binding in the rat central nervous system
Stein EA; Hiller JM; Simon EJ
1992 Dec;51(3):683-690, Neuroscience
The endogenous opioid peptides are known to play a significant role in the modulation and/or mediation of numerous environmental or experimental stressors. However, the specific opioid peptide(s) and receptor type(s) involved, under what physiologic conditions they are engaged and within which regions of the CNS is not well understood. We therefore examined the effects of both a chronic and an acute stressor-90-h water deprivation and a single 20-min foot shock on opioid receptor binding in 17 specific rat brain nuclei. [3H]DSTLE (Tyr-D-Ser-Gly-Phe-Leu-Thr) and [3H]DAGO(Tyr-D-Gly-Phe-NMe-Phe-Gly-ol) were used to label delta and mu receptors, respectively. Foot shock induced profound antinociception as measured by tail-flick latency which outlasted the stressor by several minutes. However, only the septum responded with a decrease in [3H]DAGO binding to this type of stress-induced analgesia. No other alterations in either [3H]DAGO or [3H]DSTLE binding were seen in response to foot shock. In contrast, water deprivation induced increases in [3H-DAGO] binding in the septum as well as increases in [3H]DSTLE binding in the caudate and accumbens nuclei. Moreover, the presumptive mild stress of handling in the foot shock control group was sufficient to decrease mu or delta receptor binding in seven out of 17 brain regions investigated (including the frontal cortex and olfactory tubercle where both mu and delta binding were increased) when compared to unhandled deprivation control animals. These changes in opioid receptor binding may have been the result of alterations in treatment-induced peptide release, receptor regulation, or interactions with other released neurotransmitter ligand/receptor complexes.(ABSTRACT TRUNCATED AT 250 WORDS)
— id: 62294, year: 1992, vol: 51, page: 683, stat: Journal Article,

Are the preservatives sodium bisulfite and ethylene diaminetetraacetate free from neurotoxic involvement?
Wang BC; Budzilovich G; Hiller JM; Simon EJ; Hillman DE; Li D; Turndorf H
1992 Oct;77(3):602-604, Anesthesiology
— id: 45792, year: 1992, vol: 77, page: 602, stat: Journal Article,

Distribution of 3H-morphine after lumbar epidural administration in unanesthetized rabbits
Wang BC; Hiller JM; Simon EJ; Hillman DE; Rosenberg C; Turndorf H
1992 Nov-Dec;17(6):334-339, Regional anesthesia
BACKGROUND AND OBJECTIVES. This study focused on the distribution of 3H-morphine in the spinal cord, roots, urine, and blood, after epidural administration in rabbits. METHODS. Under nitrous oxide, halothane, and oxygen endotracheal anesthesia, the cisterna magna of New Zealand albino rabbits was cannulated for cerebrospinal fluid sampling, and catheters were placed in the lumbar epidural space. Through the epidural catheter, 200 pmol of 3H-morphine contained in 500 microliters of 1.3 mM (0.21 mg) morphine was injected. Arterial blood and cisternal CSF were sampled at 0, 5, 15, 30, 45, 60, 90, and 120 minutes after injection. Animals were killed with intravenous pentobarbital at the end of 120 minutes (n = 3), 6 hours (n = 4), and 12 hours (n = 2). In each animal the brain, spinal cord, spinal roots, liver, kidneys, and urinary bladder were removed. RESULTS. The injection site over the cord was identified and all tissues were immediately frozen at -70 degrees C. Two-mm thick cross-sections, were taken from every centimeter of the spinal cord. Radioactivity in the series of sections was determined by scintillation spectroscopy. At 2 hours, 4.2% +/- 1.1% of the injected radioactivity was recovered, and at 6 hours 1.6% +/- 0.6% was recovered. Radioactivity was concentrated mainly around the lumbar injection site, and it decreased as the distance increased from the injection site and coincided with elapsed time after the injection. CONCLUSION. Multiple linear regression analysis of radioactive labels showed the significant effect of time, distance from the injection site, and the time-distance interaction on the distribution of 3H-morphine in the spinal cord (p < 0.0001 for time and rostral and caudal distance from the injection site; and p < 0.0001 for interaction between time and distance.) A major portion of the injected radioactivity was recovered in the urine and a small amount in other tissues and body fluid: bladder, liver, spinal roots, kidney, plasma, and cerebrospinal fluid
— id: 8205, year: 1992, vol: 17, page: 334, stat: Journal Article,

Analgesia following subarachnoid sodium ibuprofen in rats
Wang BC; Hiller JM; Simon EJ; Li D; Rosenberg C; Turndorf H
1992 ;77:A862-A862, Anesthesiology
— id: 47354, year: 1992, vol: 77, page: A862, stat: Journal Article,

Lumbar subarachnoid ethylenediaminetetraacetate induces hindlimb tetanic contractions in rats: prevention by CaCl2 pretreatment; observation of spinal nerve root degeneration
Wang BC; Li D; Hiller JM; Simon EJ; Budzilovich G; Hillman DE
1992 Dec;75(6):895-899, Anesthesia & analgesia
Disodium ethylenediaminetetraacetate (Na2EDTA) has replaced sodium bisulfite as the antioxidant in 2-chloroprocaine, Nesacaine CE. This study was undertaken to determine whether this new formulation has neurotoxic effects when administered in the subarachnoid space. Sprague-Dawley rats receiving subarachnoid injections of 1.5 mM or higher concentrations of Na2EDTA immediately initiated a circling behavior that was followed by the development of tetanic contractions of the hindlimbs lasting for 15-20 min. The tetanic contractions were followed by a brief period of hindlimb paralysis. Pretreatment of rats by subarachnoid injections of 1 mM CaCl2 prevented the development of tetanic contractions and paralysis of the hindlimb. Histologic examination of animals receiving Na2EDTA revealed moderate to severe focal degenerative changes in spinal nerve roots. Control rats receiving subarachnoid injections of normal saline solution did not develop tetanic contraction nor pathological changes on light microscopy. These results suggest that the preservative used in Nesacaine-MPF may be neurotoxic
— id: 13356, year: 1992, vol: 75, page: 895, stat: Journal Article,

Examining the analgesic effect of epidural bestatin and its low dose combination with clonidine in rats
Wang BC; Li D; Hiller JM; Simon EJ; Rosenberg C; Turndorf H
1992 ;17:3S84-3S84, Regional anesthesia
— id: 47291, year: 1992, vol: 17, page: 3S84, stat: Journal Article,

Effects of parabrachial opioid antagonism on stimulation-induced feeding
Carr KD; Aleman DO; Bak TH; Simon EJ
1991 Apr 5;545(1-2):283-286, Brain research
The pontine parabrachial nucleus (PBN) contains gustatory relay neurons and a high concentration of opioid receptors. To investigate the involvement of PBN opioid activity in feeding behavior, antagonists were infused into the PBN bilaterally and effects on stimulation-induced feeding were determined. Naloxone, a mu-preferring antagonist, increased the lateral hypothalamic stimulation threshold for eliciting feeding behavior while nor-binaltorphimine, a kappa-selective antagonist, did not. Neither antagonist increased threshold when infused into dorsal pontine sites outside of the PBN or the fourth ventricle. In as much as PBN contains mu and kappa but no detectable delta receptors, the present results suggest that mu opioid activity within the PBN is involved in the mediation of feeding behavior
— id: 14069, year: 1991, vol: 545, page: 283, stat: Journal Article,

Opioid receptors and endogenous opioid peptides
Simon EJ
1991 Jul;11(4):357-374, Medicinal research reviews
— id: 13988, year: 1991, vol: 11, page: 357, stat: Journal Article,

Subarachnoid disodium EDTA induces concentration-dependent tetanic contraction in rats: prevention by CaCl2 pretreatment
Wang BC; Li D; Hiller JM; Simon EJ; Budzilovich G
1991 ;75:A651-A651, Anesthesiology
— id: 47363, year: 1991, vol: 75, page: A651, stat: Journal Article,

Epidural EDTA induces tetanic contractions in rats
Wang BC; Li D; Hiller JM; Simon EJ; Budzilovich G; Turndorf H
1991 ;72:S312-S312, Anesthesia & analgesia
— id: 47232, year: 1991, vol: 72, page: S312, stat: Journal Article,

No-carrier-added (NCA) N-(3-[18F]fluoropropyl)-N-norbuprenorphine and N-(3-[18F]fluoropropyl)-N-nordiprenorphine--synthesis, anatomical distribution in mice and rats, and tomographic studies in a baboon
Bai LQ; Teng RR; Shiue CY; Wolf AP; Dewey SL; Holland MJ; Simon EJ
1990 ;17(2):217-227, International journal of radiation applications & instrumentation. Pt. B. Nuclear medicine & biology
N-(3-Fluoropropyl)-N-norbuprenorphine (3a) and N-(3-fluoropropyl)-N-nordiprenorphine (4a) were synthesized by N-alkylation of norbuprenorphine (1) and nordiprenorphine (2) with 1-bromo-3-fluoropropane. The corresponding no-carrier-added (NCA) N-(3-[18F]fluoropropyl)-N-norbuprenorphine (3b) and N-(3-[18F]fluoropropyl)-N-nordiprenorphine (4b) were synthesized by N-alkylation of 1 and 2 with NCA 1-[18F]fluoro-3-iodopropane in a synthesis time of approximately 100 min from end of bombardment (EOB) with an overall radiochemical yield of approximately 15% (EOB) and a mass of 2-3 nmol. In vitro studies indicate that in the absence of sodium chloride, compounds 3a, 4a, N-propyl-N-norbuprenorphine (5), buprenorphine and diprenorphine are reasonably comparable in binding affinity for opioid receptors. In the presence of 100 mM sodium chloride, however, compounds 3a, 4a and 5, are clearly less potent than buprenorphine and diprenorphine. The anatomical distribution study of compound 3b in mice shows radioactivity accumulating in bone, indicating that in vivo defluorination may have occurred. Rat studies of both compounds 3b and 4b indicate the specific distribution of these two radioligands within certain cortical and subcortical regions of rat brain. However, the absolute uptake of compound 4b in rat brain was only half that of compound 3b. PET studies of 3b in a baboon revealed specific binding of compound 3b in striatum and cerebellum. At 1 h after injection, ratios of specific/non-specific binding of 3b in striatum and cerebellum of a baboon were 1.9 and 1.7 respectively
— id: 63631, year: 1990, vol: 17, page: 217, stat: Journal Article,

Differential effects of cyanogen bromide on ligand binding by mu, delta and kappa opioid receptors
Hiller JM; Fan LQ; Simon EJ
1990 ;47(24):2225-2230, Life sciences
Guinea pig brain membranes treated with cyanogen bromide (CNBr) demonstrate a loss in the number of mu opioid receptors and a lower binding affinity of delta opioid receptors. These receptor changes are irreversible. Results from ligand protection experiments support the hypothesis that the location of the methionine groups, the sites at which CNBr cleaves peptides, differs between these two types of opioid receptors. Kappa receptors are significantly less sensitive to the action of CNBr than mu or delta receptors
— id: 62235, year: 1990, vol: 47, page: 2225, stat: Journal Article,

Electrophilic alpha-methylene-gamma-lactone and isothiocyanate opioid ligands related to etorphine
Klein P; Nelson WL; Yao YH; Simon EJ
1990 Aug;33(8):2286-2296, Journal of medicinal chemistry
Isothiocyanate and alpha-methylene-gamma-lactone analogues of 6,14-endo-ethenotetrahydrothebaine and -oripavine were prepared with the electrophilic groups being located at C-19 in the C-7 alpha-side chain. Isothiocyanates were prepared in the N-Me and N-CPM (N-cyclopropylmethyl) series, both as the phenols and 3-O-methyl ethers from the diastereomeric amines formed from reductive amination of thevinone (2) and N-(cyclopropylmethyl)northevinone (13). Although addition of the organozinc reagent from methyl alpha-bromomethacrylate to 25 failed, addition to 3-O-protected aldehydes 27 and 35 produced, after subsequent deprotection, alpha-methylene-gamma-lactones 29 and 37, respectively. In the opioid receptor displacement assays against [3H]bremazocine as the radiolabeled ligand, the phenolic compounds were most potent with N-CPM isothiocyanates 20 and 21 showing IC50s of 0.32 and 0.76 nM, respectively, and N-CPM alpha-methylene-gamma-lactone 37 having an IC50 = 1.0 nM. Compound 37 showed irreversible effects in the binding assay which were mu-selective, as demonstrated by analogous experiments using [3H]DAGO, and naloxone was found to protect against the irreversible effects. This observation suggests that a receptor-bound nucleophile is located at a position where it can readily reach the alpha-methylene group of lactone 37
— id: 63629, year: 1990, vol: 33, page: 2286, stat: Journal Article,

Conjugate addition ligands of opioid antagonists. Methacrylate esters and ethers of 6 alpha- and 6 beta-naltrexol
Olsen LD; Klein P; Nelson WL; Yao YH; Simon EJ
1990 Feb;33(2):737-741, Journal of medicinal chemistry
Alpha- and beta-naltrexol derived esters 9 and 10 and ethers 11 and 12, each containing the alpha, beta-unsaturated ester functionality, were prepared as conformationally more flexible analogues of spiro-alpha-methylene-gamma-lactones 5 and 6. All were active in the opioid radioreceptor binding assay against [3H]bremazocine and more active against [3H]DAGO, indicating mu-subtype selectivity, but only ether 12 showed significant irreversible activity. We conclude that small structural changes, made in very closely related electrophilic opioids, lead to changes in receptor binding. All four compounds were long-acting antagonists to morphine in mice, with ester 10 being approximately equipotent with naltrexone
— id: 63630, year: 1990, vol: 33, page: 737, stat: Journal Article,

Cross-linking of human [125I]beta-endorphin to opioid receptors in rat striatal membranes: biochemical evidence for the existence of a mu/delta opioid receptor complex
Schoffelmeer AN; Yao YH; Gioannini TL; Hiller JM; Ofri D; Roques BP; Simon EJ
1990 Apr;253(1):419-426, Journal of pharmacology & experimental therapeutics
In a modified Krebs buffer at 37 degrees C, the selective mu agonist [3H] D-Ala2,MePhe4,Gly-ol5]enkephalin [( 3H]DAMGO) and the nonselective mu/delta agonist human [125I]beta-endorphin [( 125I]beta-endH) bound to rat striatal membranes with a Kd of about 7 and 5 nM and a Bmax of about 95 and 260 fmol/mg of protein, respectively, consistent with labeling of mu receptors by the former ligand and labeling of both mu and delta receptors by the latter. The binding of 2 nM [125I]beta-endH was displaced by unlabeled DAMGO (IC50 30 nM), [D-Ala2-D-Leu5]enkephalin (IC50 60 nM) as well as by the selective delta agonists [D-Ser2(O-tert-butyl),Leu5]enkephalyl-Thr6 (DSTBULET, IC50 500 nM) and Tyr-Ala-Phe-Asp-Val-Val-Gly-NH2 (IC50 700 nM) in a monophasic manner within 2 to 3 log concentration units, suggesting an allosteric interaction between mu and delta sites labeled by [125I]beta-endH under these conditions. Accordingly, 500 nM DSTBULET caused almost 40% inhibition of the apparent Bmax without changing the apparent Kd of [3H] DAMGO. The kappa agonist U 50,488 was ineffective as competing ligand even at a concentration of 10 microM. Upon affinity cross-linking of [125I]beta-endH (2 nM) to rat striatal mu- and delta-opioid receptors, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the solubilized tissue under reducing conditions followed by autoradiography of the dried gels revealed a major broad band of covalently labeled protein with an apparent molecular weight of 80 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)
— id: 42061, year: 1990, vol: 253, page: 419, stat: Journal Article,

Cross-linking of 125I-beta-endorphin to rat striatal mu- and delta-opioid receptors under physiological conditions: evidence for an opioid receptor complex
Schoffelmeer AN; Yao YH; Simon EJ
1990 ;328:105-108, Progress in clinical & biological research
— id: 63633, year: 1990, vol: 328, page: 105, stat: Journal Article,

Brain stimulation-induced feeding alters regional opioid receptor binding in the rat: an in vivo autoradiographic study
Stein EA; Carr KD; Simon EJ
1990 Nov 19;533(2):213-222, Brain research
Although opioid antagonists block feeding behavior in a variety of animal models, the number and identity of CNS regions in which the inferred endogenous opioid activity mediates feeding have yet to be established. Furthermore, it is not yet clear whether the opioid activity that sustains feeding is a concomitant of the appetitive motivational state or the consummatory response. In an effort to address these issues, an in vivo autoradiographic method was used to visualize CNS regional changes in opioid release during appetitively motivating electrical stimulation in the lateral hypothalamus (ESLH) and during consummatory behavior elicited by such stimulation. Regional decreases in [3H]diprenorphine [(3H]Dpr) binding, suggesting increased release of an endogenous opioid peptide, were observed in the medial prefrontal cortex, medial septum, gustatory cortex, zona incerta, mediodorsal thalamus, and hippocampus of rats receiving ESLH. Decreased binding in the latter 4 structures did not appear when animals were allowed to eat during ESLH, suggesting that the inferred opioid release is associated with appetitive behaviors elicited by ESLH which are suppressed when food is available and consummatory behavior predominates. When animals were allowed to eat during ESLH, [3H]Dpr binding in anterior cingulate cortex decreased substantially, suggesting that feeding behavior specifically triggers opioid release in this region. ESLH and feeding were found to increase [3H]Dpr binding in a number of CNS regions. Alternative explanations for increased binding, including inhibition of tonic opioid release, changes in cerebral blood flow, and opioid receptor up-regulation are discussed
— id: 62163, year: 1990, vol: 533, page: 213, stat: Journal Article,

Stimulus induced feeding alters regional opiate receptor binding in the rat: an in vivo audioradiographic study
Stein EA; Carr KD; Simon EJ
1990 ;328:187-190, Progress in clinical & biological research
— id: 63632, year: 1990, vol: 328, page: 187, stat: Journal Article,

A preliminary evaluation of analgesic latency of epidural analgesics in rabbits
Wang BC; Hiller JM; Simon EJ; Dubzilovich G; Hillman DE; Turndorf H
1990 ;40:S127-S127, Pain
— id: 47260, year: 1990, vol: 40, page: S127, stat: Journal Article,

Epidural meperidine does not significantly increase urinary bladder size: a cystographic study in rabbits
Wang BC; Hiller JM; Simon EJ; Hillman DE; Li D; Rosenberg C; Turndorf H
1990 ;15:1S30-1S30, Regional anesthesia
— id: 47293, year: 1990, vol: 15, page: 1S30, stat: Journal Article,

Selection of vehicle for epidural meperidine influences nociceptive latency in rabbits
Wang BC; Hiller JM; Simon EJ; Hillman DE; Li D; Rosenberg C; Turndorf H
1990 Jun;37(4 Pt 2):S47-S47, Canadian journal of anaesthesia
— id: 45794, year: 1990, vol: 37, page: S47, stat: Journal Article,

Low dose epidural clonidine enhances morphine analgesia withou causing hypotension in rabbits
Wang BC; Hiller JM; Simon EJ; Li D; Rosenberg C; Turndorf H
1990 ;73:A806-A806, Anesthesiology
— id: 47374, year: 1990, vol: 73, page: A806, stat: Journal Article,

Subarachnoid EDTA induces hindlimb myoclonous in rats
Wang BC; Li D; Hiller JM; Simon EJ; Dubzilovich G; Hillman DE; Turndorf H
1990 ;73:A1259-A1259, Anesthesiology
— id: 47375, year: 1990, vol: 73, page: A1259, stat: Journal Article,

OPIOID LIGANDS RELATED TO TIFLUADOM
Archer, S; Seyedmozaffari, A; Simon, EJ; Gioannini, TL
1989 Nov-Dec;24(6):569-572, European journal of medicinal chemistry
— id: 31900, year: 1989, vol: 24, page: 569, stat: Journal Article,

Effects of the selective kappa opioid antagonist, nor-binaltorphimine, on electrically-elicited feeding in the rat
Carr KD; Bak TH; Simon EJ; Portoghese PS
1989 ;45(19):1787-1792, Life sciences
Lateral ventricular injections of the 'nonspecific' opioid antagonist naloxone (100 micrograms) and the kappa-selective opioid antagonist nor-binaltorphimine (50 micrograms) elevated the electrical brain stimulation frequency threshold for eliciting feeding behavior. Mesopontine aqueductal injections of nor-binaltorphimine, on the other hand, lowered the feeding threshold while naloxone still elevated threshold. These findings suggest the existence of forebrain kappa receptors at which endogenous opioid activity results in a facilitation of feeding while kappa receptors in the brainstem seem to mediate an inhibitory effect
— id: 10828, year: 1989, vol: 45, page: 1787, stat: Journal Article,

Evidence for the presence of disulfide bridges in opioid receptors essential for ligand binding. Possible role in receptor activation
Gioannini TL; Liu YF; Park YH; Hiller JM; Simon EJ
1989 Jul;2(1):44-48, Journal of molecular recognition
The mobility of purified mu opioid binding protein in SDS-polyacrylamide gek electrophoresis is sensitive to the presence of reducing agents. In the presence of increasing concentrations of DTT the apparent molecular weight increases in a stepwise fashion from 53 kDa to 65 kDa. This reduction in mobility is attributed to the successive breakage of disulfide bridges, resulting in an increasingly asymmetric molecule. Treatment of cell membranes from various brain areas with reducing agents, such as DTT, produced a concentration-dependent inhibition of opioid binding. Sensitivity to DTT inhibition varied between receptor types, mu greater than delta much greater than kappa. For mu receptors, agonist binding was considerably more sensitive to DTT than antagonist binding. Inhibition by DTT is readily reversible and is unaffected by Na+ and/or Mg2+ ions. Reversibility may be partially prevented by the inclusion of a low concentration of a reducing reagent such as glutathione which does not inhibit binding but blocks reformation of disulfide bonds. Scatchard analysis of saturation data shows that DTT causes a pronounced decrease in binding affinity with little effect on receptor number. It is suggested that disulfide bonds are essential for ligand binding and that cleavage of one or more of these bonds may play a role in opioid receptor activation by agonists
— id: 10567, year: 1989, vol: 2, page: 44, stat: Journal Article,

Pharmacokinetics of [3H]-buprenorphine in the rat
Holland MJ; Carr KD; Simon EJ
1989 Apr;64(1):3-16, Research communications in chemical pathology & pharmacology
The present study was undertaken to evaluate the potential usefulness of 11C-buprenorphine (bup) as a ligand for investigating opioid receptors in living primates, including humans, using positron-emission transaxial tomography (PETT). Because PETT studies of receptor function are best carried out under conditions of low receptor occupancy, the pharmacokinetics, uptake into brain, and specific binding to opioid receptors within brain of 3H-bup were examined in rats under conditions in which occupancy of opioid receptors by 3H-bup never exceeded 2% of sites in the brain at any time point examined. Male Sprague Dawley rats (weight range 140-220 grams) were injected s.c. with either naloxone (10 mg/kg) or saline. Five min later, a saline solution containing [15, 16-3H] bup (39 Ci/mmole) was injected into tail veins at a dose of 0.4 microgram/kg body weight. At least 90-95% of radioactivity was cleared from the blood in the first 5 min. In saline pretreated rats, total brain uptake 15 min after injection of 3H-bup was about 0.4% of the administered dose. Ligand specifically bound to receptors may be estimated by comparing the amount of radioactivity in the brain following injection of labeled ligand alone to that obtained when a high concentration of an unlabeled competitor is pre- or co-administered. In the present study, average levels obtained in brain (excluding cerebellum) were higher in saline pretreated rats than in naloxone pretreated rats at all time points and the difference increased with time indicating specific binding to opioid receptors. Specific binding may also be estimated by comparing radioactivity accumulated in brain areas rich in opioid receptors with 'background' levels achieved in areas known to be low in opioid receptors, e.g., the cerebellum in rats. In the present study, ratios of the amount of radioactivity in brain (excluding cerebellum) to the amount in the cerebellum increased with time (to about 4 after 60 min) in saline pretreated rats, but remained close to 1 in naloxone pretreated rats. The effects of biological variation were less when specific binding was estimated by the latter method since each animal served as its own control. Tissue distribution of radioactivity to other tissues (blood, skin, muscle, fat, liver, kidney) was similar in naloxone and saline pretreated rats. The results presented here suggest that 11C-bup or an 18F-labeled fluorinated derivative would be a useful ligand for PETT studies
— id: 10690, year: 1989, vol: 64, page: 3, stat: Journal Article,

Cross-linking of human 125I-beta-endorphin to a mu-delta opioid receptor complex in rat striatum
Schoffelmeer AN; Yao YH; Simon EJ
1989 Jul 18;166(2):357-358, European journal of pharmacology
— id: 10545, year: 1989, vol: 166, page: 357, stat: Journal Article,

CNS REGIONAL CHANGES IN TRITIATED DIPRENORPHINE BINDING FOLLOWING ELECTRICALLY ELICITED FEEDING IN THE RAT
STEIN E A; CARR K D; SIMON E J
1989 ;15(1):896-896, Abstracts (Society for Neuroscience)
— id: 92230, year: 1989, vol: 15, page: 896, stat: Journal Article,

Distribution of 3H-morphine following lumbar subarachnoid injection in unanesthetized rabbits
Wang BC; Hiller JM; Simon EJ; Hillman DE; Rosenberg C; Turndorf H
1989 May;70(5):817-824, Anesthesiology
Morphine sulfate (40-100 micrograms) and 3H-morphine (125-200 pmol) were injected into the lumbar subarachnoid space of 18 unanesthetized rabbits through a surgically implanted catheter. Radioactivity remaining in the spinal cord 2, 4, 6, and 12 h later revealed recovery (mean +/- SEM) of 45 +/- 5.6% (n = 3), 30.5 +/- 14.1% (n = 4), 11.23 +/- 4.4% (n = 3), and 3.7 +/- 1.1% (n = 3), respectively, of the injected radioactivity. Tritiated morphine was found to be predominantly centered around the injection site, with limited rostral and caudal spread in the cord. No significant radioactivity was detected in plasma or cerebrospinal fluid (CSF) samples from the cisterna magna taken at 5, 15, 30, min and 1, 2, 4, 6, 12, and 24 h after receiving radioactive labeled drug (with the exception of that in one rabbit). Of the injected radioactivity, 75% was recovered in the urine in 12 h. These results suggest that the persistence of morphine in the spinal cord could account for its prolonged analgesic effect following intrathecal administration
— id: 10634, year: 1989, vol: 70, page: 817, stat: Journal Article,

Is EDTA inocuous in the subarachnoid space?
Wang BC; Hiller JM; Simon EJ; Hillman DE; Spielholz N; Turndorf H
1989 ;14:2S72-2S72, Regional anesthesia
— id: 47294, year: 1989, vol: 14, page: 2S72, stat: Journal Article,

Is EDTA harmless in the subarachnoid space?
Wang BC; Hiller JM; Simon EJ; Hillman DE; Turndorf H
1989 ;71:A1142-A1142, Anesthesiology
— id: 47384, year: 1989, vol: 71, page: A1142, stat: Journal Article,

Recovery of lidocaine following interpleural injection in rabbit
Wang BC; Hiller JM; Simon EJ; Sue JL; Turndorf H
1989 ;71:A746-A746, Anesthesiology
— id: 47385, year: 1989, vol: 71, page: A746, stat: Journal Article,

OPPOSITE EFFECTS OF ROSTRAL AND CAUDAL VENTRICULAR INFUSION OF NOR-BINALTORPHIMINE ON STIMULATION-INDUCED FEEDING
BAK T; CARR K D; SIMON E J; PORTOGHESE P S
1988 ;14(2):1107-1107, Abstracts (Society for Neuroscience)
— id: 92231, year: 1988, vol: 14, page: 1107, stat: Journal Article,

ANTIBODIES TO DYNORPHIN A 1-8 AND 1-17 ELEVATE THRESHOLD FOR BRAIN STIMULATION-INDUCED FEEDING IN RAT
CARR K D; BAK T H; SIMON E J
1988 ;14(2):1107-1107, Abstracts (Society for Neuroscience)
— id: 92232, year: 1988, vol: 14, page: 1107, stat: Journal Article,

Regulation of electrically elicited feeding in the rat by CNS opioid peptides
Carr KD; Simon EJ
Regulatory roles of opioid peptides Weinheim : VCH Publishers, 1988,
— id: 3427, year: 1988, vol: , page: 378, stat: Chapter,

Affinity crosslinking of 125I-labeled human beta-endorphin to cell lines possessing either mu- or delta-type opioid binding sites
Keren O; Gioannini TL; Hiller JM; Simon EJ
1988 Feb 9;440(2):280-284, Brain research
The specific labeling of opioid receptor-related polypeptides was compared in two cell lines which differ in their opioid receptor population: SK-N-SH which contains predominantly mu-type opioid receptors, and NG-108-15, which contains exclusively delta-type opioid receptors. Labeling of opioid receptors was achieved by affinity cross-linking of membranes, using 125I-labeled human beta-endorphin, followed by solubilization in sodium dodecyl sulphate (SDS), SDS-gel electrophoresis and autoradiography. Different labeling patterns were obtained from these two cell lines. In SK-N-SH cells, 3 major proteins were labeled, corresponding to molecular weights of 92, 65 and 25 kDa, while in the NG-108-15 cells, 53-kDa and 25-kDa polypeptides were the major ones labeled. The radioactivity incorporated into the 92- and 65-kDa peptide bands derived from SK-N-SH cells was displaced by the mu-selective ligand Tyr-D-Ala-Gly-MePhe-Gly-ol (DAGO) but not by the delta-selective ligand [D-Pen2,D-Pen5]enkephalin (DPDPE). The radioactivity incorporated into the NG-108-15-derived peptide bands was displaced by the delta-selective ligand, but not by the mu-selective ligand. This confirms our previous finding in mammalian brain which demonstrated that mu- and delta-opioid binding sites can be identified as distinct proteins which differ in molecular size
— id: 11184, year: 1988, vol: 440, page: 280, stat: Journal Article,

CITATION CLASSIC - STEREOSPECIFIC BINDING OF THE POTENT NARCOTIC ANALGESIC [H-3]ETORPHINE TO RAT-BRAIN HOMOGENATE
Simon, EJ
1988 Oct 10;48(41):19-19, Current contents. Life sciences
— id: 31590, year: 1988, vol: 48, page: 19, stat: Journal Article,

Urinary retention after intrathecal morphine in rabbits
Wang BC; Hiller J; Simon E; Hillman D; Turndorf H
1988 ;13:1S34-1S34, Regional anesthesia
— id: 47298, year: 1988, vol: 13, page: 1S34, stat: Journal Article,

Intravenous cystogram for study of urinary retention following intrathecal morphine in unanesthetized rabbits
Wang BC; Hiller JM; Simon EJ; Hillman DE; Turndorf H
1988 Jul;68(6):962-964, Anesthesiology
— id: 45796, year: 1988, vol: 68, page: 962, stat: Journal Article,

Is rostral spread the sole cause of respiratory depression after intrathecal morphine?
Wang BC; Hiller Jm; Simon EJ; Hillman DE; Turndorf H
1988 ;13:2S30-2S30, Regional anesthesia
— id: 47299, year: 1988, vol: 13, page: 2S30, stat: Journal Article,

Effects of stress and beta-funal trexamine pretreatment on morphine analgesia and opioid binding in rats
Adams JU; Andrews JS; Hiller JM; Simon EJ; Holtzman SG
1987 Dec 28;41(26):2835-2844, Life sciences
This study was essentially an in vivo protection experiment designed to test further the hypothesis that stress induces release of endogenous opioids which then act at opioid receptors. Rats that were either subjected to restraint stress for 1 hr or unstressed were injected ICV with either saline or 2.5 micrograms of beta-funaltrexamine (beta-FNA), an irreversible opioid antagonist that alkylates the mu-opioid receptor. Twenty-four hours later, subjects were tested unstressed for morphine analgesia (tail-flick assay) or were sacrificed and opioid binding in brain was determined. [3H]D-Ala2NMePhe4-Gly5(ol)enkephalin (DAGO) served as a specific ligand for mu- opioid receptors, and [3H]-bremazocine as a general ligand for all opioid receptors. Rats injected with saline while stressed were significantly less sensitive to the analgesic action of morphine 24 hr later than were their unstressed counterparts. Beta-FNA pretreatment attenuated morphine analgesia in an insurmountable manner. Animals pretreated with beta-FNA while stressed were significantly more sensitive to the analgesic effect of morphine than were animals that received beta-FNA while unstressed, consistent with the hypothesis that stress induces release of endogenous opioids that would protect opioid receptors from alkylation by beta-FNA. beta-FNA caused small and similar decreases in [3H]-DAGO binding in brain of both stressed and unstressed animals. Stressed rats injected with saline tended to have increased levels of [3H]DAGO and [3H]-bremazocine binding compared to the other groups. This outcome may be relevant to the tolerance to morphine analgesia caused by stress
— id: 23566, year: 1987, vol: 41, page: 2835, stat: Journal Article,

ANTIBODIES TO DYNORPHIN A 1-13 BUT NOT BETA ENDORPHIN INHIBIT ELECTRICALLY-ELICITED FEEDING IN THE RAT
CARR K D; BAK T H; GIOANNIN T L; SIMON E J
1987 ;13(2):877-877, Abstracts (Society for Neuroscience)
— id: 92233, year: 1987, vol: 13, page: 877, stat: Journal Article,

Antibodies to dynorphin A(1-13) but not beta-endorphin inhibit electrically elicited feeding in the rat
Carr KD; Bak TH; Gioannini TL; Simon EJ
1987 Oct 6;422(2):384-388, Brain research
Highly specific antibodies to dynorphin A(1-13), infused into the lateral ventricle, elevated brain stimulation threshold for eliciting feeding behavior. Antibodies to beta-endorphin had little or no effect. Temporal analysis of the anorectic action indicated a striking similarity to the effect of systemically administered naloxone. These findings suggest that central dynorphin is involved in the control of ingestive behavior and that the anorectic action of naloxone may result from antagonism of dynorphinergic transmission
— id: 11344, year: 1987, vol: 422, page: 384, stat: Journal Article,

IRREVERSIBLE LABELING OF OPIOID RECEPTORS WITH THE AID OF ARYLDIAZONIUM SALTS DERIVED FROM FENTANYL
GALZI, JL; ILIEN, B; SIMON, EJ; GOELDNER, M; HIRTH, C
1987 JAN 26 ;28(4):401-404, Tetrahedron letters
— id: 41743, year: 1987, vol: 28, page: 401, stat: Journal Article,

Selective changes in mu, delta and kappa opioid receptor binding in certain limbic regions of the brain in Alzheimer's disease patients
Hiller JM; Itzhak Y; Simon EJ
1987 Mar 17;406(1-2):17-23, Brain research
Total opioid binding and levels of the three major types of opioid binding sites were measured in homogenates of various limbic structures from post-mortem brains of Alzheimer's disease patients and age-matched control individuals. The most consistent finding in Alzheimer's disease brains was an increase in kappa binding in all 6 areas of the limbic system examined, with the putamen and caudate regions showing significant increases of 114% and 53%, respectively. In addition, the Alzheimer's disease putamen showed a significantly higher level of total binding (85% increase). The amygdala of Alzheimer's disease patients exhibited significantly lower levels of mu and delta binding (41% and 55% decrease, respectively). Total binding and binding to mu and delta receptors in frontal cortex, caudate and hippocampus of Alzheimer's disease brains was indistinguishable from levels seen in these brain areas from control individuals
— id: 62164, year: 1987, vol: 406, page: 17, stat: Journal Article,

[3H]-BUPRENORPHINE DISSOCIATION FROM OPIATE RECEPTORS INVIVO
Holland, MJC; Carr, KD; Simon, EJ
1987 Mar 1;46(3):868-868, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 31267, year: 1987, vol: 46, page: 868, stat: Journal Article,

No-carrier-added (NCA) (+/-)-N-(3-[18F]fluoropropyl)-N-normetazocine-synthesis and PET studies in a baboon
Shiue CY; Teng RR; Bai LQ; Wolf AP; Arnett CD; Simon EJ
1987 ;14(2):119-122, International journal of radiation applications & instrumentation. Pt. B. Nuclear medicine & biology
No-carrier-added (NCA) (+/-)-N-(3-[18F]Fluoropropyl)-N-normetazocine (2) was synthesized by N-alkylation of (+/-)-N-normetazocine (1) with NCA 1-[18F]fluoro-3-iodopropane in an overall radiochemical yield of 10% (EOB) with a mass of 3.5 nmol in a synthesis time of 90 min from end of bombardment (EOB). PET studies of 2 in a baboon did not indicate specificity for opiate receptor sites alone: The activity declined rapidly in the striatum, the frontal cortex and the cerebellum. The baboon total arterial plasma radioactivity clearance was very rapid and the metabolism of compound 2 in plasma was also very rapid. These results suggest that compound 2 is not a suitable radioligand for imaging opiate receptors in the human brain by positron tomography
— id: 63635, year: 1987, vol: 14, page: 119, stat: Journal Article,

Recent studies on heterogeneity and isolation of opioid receptors
Simon EJ
1987 ;76:35-41, NIDA research monograph series
— id: 11430, year: 1987, vol: 76, page: 35, stat: Journal Article,

Subunit structure and purification of opioid receptors
Simon EJ
1987 ;7(1-4):105-132, Journal of receptor research
Considerable evidence indicates the existence of multiple types of opioid receptors. The three major types have been named mu, delta and kappa. The earlier evidence was based on pharmacological as well as membrane binding experiments. This paper will emphasize more recent studies using solubilized opioid binding sites. Several laboratories, including our own, have succeeded in separating kappa receptors from other types. A similar separation of mu from delta receptors has not yet been achieved. By crosslinking experiments with 125I- human beta-endorphin we have been able to provide strong evidence for differences in molecular size between the major binding components of mu (65K) and delta (53K) receptors. It is not yet established whether the difference resides in the protein or carbohydrate portion of these glycoproteins. These results suggest that the three major types of opioid receptors represent distinct molecular entities. An active opioid binding protein solubilized from bovine striatal membranes has been purified to apparent homogeneity. The major purification steps involve affinity chromatography and lectin chromatography on immobilized wheat germ agglutinin. The purified material gave a single band of molecular weight 65K Da on SDS-PAGE. Its specific activity for opioid binding was ca. 13,000 pmol/mg protein and its properties are those of a component of the mu receptor
— id: 62273, year: 1987, vol: 7, page: 105, stat: Journal Article,

Interaction with lectin of kappa opioid binding sites solubilized from human placenta
Valette A; Rouge P; Coulais E; Potonnier G; Cros J; Simon EJ
1987 Feb 9;40(6):535-540, Life sciences
Kappa opioid binding sites from human placenta, prelabeled with 3H-etorphine and solubilized, were retained on wheat germ agglutinin (WGA) agarose and specifically eluted with N-acetylglucosamine. No significant retention was found with other immobilized lectins, including Concanavalin A (Con A), soybean seed lectin (SBA), Pisum sativum lectin (PsA), Lens culinaris Medik. lectin (LcA), and Lathyrus tingitanus lectin(LtA). About 23% of applied kappa sites were specifically eluted from WGA agarose, less than half of the proportion of rat brain opioid binding sites eluted from the same lectin (55%). Receptors from placental extracts were compared with those from other tissues enriched in either kappa or mu sites. The proportion of applied kappa sites from guinea pig cerebellum eluted specifically from WGA agarose was 36%, whereas elution of binding sites from rat thalamus and rabbit cerebellum (enriched in mu sites) was at a level of 55%. This difference in the level of retention on and elution from WGA may reflect differences in the sugar composition of the glycoproteins of the two types of receptors. Succinylation of WGA abolished its ability to retain opioid binding sites, consistent with involvement of sialic acid. However, currently available evidence suggests that differences in retention on WGA between kappa and mu sites may be due to differences in either sialic acid or N-acetylglucosamine content or both
— id: 63634, year: 1987, vol: 40, page: 535, stat: Journal Article,

Distribution of 3H morphine following lumbar epidural injection in rabbits
Wang BC; Hiller J; Hillman DE; Holland M; Simon E; Turndorf H
1987 ;12:30-31, Regional anesthesia
— id: 47300, year: 1987, vol: 12, page: 30, stat: Journal Article,

Distribution of 3H morphine following lumbar subarachnoid injection in rabbits
Wang BC; Hiller JM; Holland MJ; Simon EJ; Hillman DE; Turndorf H
1987 ;66:S185-S185, Anesthesia & analgesia
— id: 47250, year: 1987, vol: 66, page: S185, stat: Journal Article,

Distribution of 3H-morphine following lumbar epidural injection in rabbits
Wang BC; Hiller JM; Holland MJ; Simon EJ; Hillman DE; Turndorf H
1987 ;67:A253-A253, Anesthesiology
— id: 47410, year: 1987, vol: 67, page: A253, stat: Journal Article,

Sodium ions increase the binding of the antagonist peptide ICI 174864 to the delta-opiate receptor
Appelmans N; Carroll JA; Rance MJ; Simon EJ; Traynor JR
1986 Feb-Mar;7(2):139-143, Neuropeptides
The ability of N,N-diallyl-Tyr-Aib-Aib-Phe-Leu-OH (ICI 174864) to displace [3H]-[D-Ala2, D-Leu5]enkephalin bound to the delta-opioid site is increased 8-16 fold by addition of 25mM NaCl. A smaller shift is observed for the related N,N-diallyl-Tyr-Gly-Gly-psi-(CH2S)-Phe-Leu-OH (ICI 154129) but no significant shift is seen with either naloxone or diprenorphine. The results stress the importance of using the correct medium for binding assays, and suggest the changes in delta-receptor conformation induced by Na+ ions also increase peptide antagonist binding
— id: 63637, year: 1986, vol: 7, page: 139, stat: Journal Article,

OPPOSITE EFFECTS OF MEDIAL THALAMIC MU AND KAPPA OPIOID ACTIVITY ON MOTIVATIONAL-AFFECTIVE RESPONSES
CARR K D; SIMON E J
1986 ;12(2):939-939, Abstracts (Society for Neuroscience)
— id: 92235, year: 1986, vol: 12, page: 939, stat: Journal Article,

The direct demonstration of binding of mu, delta and kappa agonists to digitonin-solubilized opioid receptors from bovine striatum
Crema G; Gioannini TL; Hiller JM; Simon EJ
1986 ;75:9-12, NIDA research monograph series
Active opioid binding sites, that retain the ability to bind tritiated agonists have been obtained in good yield in digitonin/NaCl/Mg2+ extracts of morphine protected bovine striatal membranes. Ligand protection of binding sites and the presence of Mg ions were found to be absolute requirements for agonist binding in this solubilized opioid receptor preparation. Soluble preparations contained a ratio of mu: delta:kappa similar to that in the membranes
— id: 63639, year: 1986, vol: 75, page: 9, stat: Journal Article,

Limbic regions of the brain of Alzheimer's disease patients show selective changes in mu, delta and kappa opioid receptor binding
Hiller JM; Itzhak Y; Simon EJ
1986 ;75:559-562, NIDA research monograph series
Total opioid binding and levels of the three major types of opioid binding sites were measured in homogenates of various limbic structures from post-mortem brains of Alzheimer's Disease (AD) patients and age-matched control individuals. AD brains showed an increase in kappa binding in all six areas of the limbic system examined, with the putamen and caudate regions showing significant increases of 114% and 53%, respectively. In addition, the AD putamen showed a significantly higher level of total binding (85% increase). The amygdala of AD patients exhibited significantly lower levels of mu and delta binding (41% and 55% decrease, respectively)
— id: 11441, year: 1986, vol: 75, page: 559, stat: Journal Article,

Identification of distinct binding site subunits of mu and delta opioid receptors
Howard AD; Sarne Y; Gioannini TL; Hiller JM; Simon EJ
1986 Jan 28;25(2):357-360, Biochemistry
Iodinated human beta-endorphin was affinity-cross-linked to opioid receptors present in membrane preparations from bovine frontal cortex, bovine striatum, guinea pig whole brain, and rat thalamus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography revealed covalently labeled peptides of 65, 53, 41, and 38 kilodaltons (kDa). The 65- and 38-kDa peptides were present in all four tissues. The 41-kDa peptide was seen only in bovine caudate and guinea pig whole brain while the 53-kDa peptide was absent in rat thalamus. All four labeled peptides were constituents of opioid receptors since their labeling was fully suppressed by the presence of excess opiates, such as bremazocine, during binding. The distribution and levels of the labeled species in the brain tissues examined and, in earlier work, in the neuroblastoma X glioma NG 108-15 cell line suggested that the 65-kDa peptide is a binding component of mu receptors while the 53-kDa peptide is a binding subunit of delta receptors. This result was strongly supported by the finding that the labeling of the 65-kDa peptide is selectively reduced by the presence of the highly mu-selective ligand Tyr-D-Ala-Gly-(N-Me)Phe-Gly-ol (DAMGE) during binding, while while the labeling of the 53-kDa peptide is selectively reduced or eliminated by the highly mu-selective ligand [D-Pen2, D-Pen5]enkephalin (DPDPE). The labeling of the 41- and 38-kDa bands was reduced by either DAMGE or DPDPE. The relationship of these lower molecular weight opioid-binding peptides to mu and delta receptors is not understood. Several possible explanations are presented
— id: 62150, year: 1986, vol: 25, page: 357, stat: Journal Article,

SYNTHESIS AND EVALUATION OF FLUORINATED DERIVATIVES OF FENTANYL AS CANDIDATES FOR OPIATE RECEPTOR STUDIES USING POSITRON EMISSION TOMOGRAPHY
HWANG, DR; FELIU, AL; WOLF, AP; MACGREGOR, RR; FOWLER, JS; ARNETT, CD; HOLLAND, MJ; CARR, K; SIMON, EJ
1986 MAR ;23(3):277-293, Journal of labelled compounds & radiopharmaceuticals
— id: 41607, year: 1986, vol: 23, page: 277, stat: Journal Article,

Affinity crosslinking of 125I-human beta-endorphin to cell lines possessing either mu or delta type opioid binding sites
Keren O; Gioannini TL; Hiller JM; Simon EJ
1986 ;75:89-92, NIDA research monograph series
Affinity crosslinking of human 125I-beta-Endorphin to cell lines possessing either mu or delta binding sites was carried out. Autoradiography of SDS-PAGE gels from these crosslinked cell lines revealed that these two sites contain major peptide subunits that differ in molecular size. This confirms our earlier finding in mammalian brain which demonstrated separate and distinct subunits for mu and delta opioid receptors
— id: 63640, year: 1986, vol: 75, page: 89, stat: Journal Article,

COMPUTER AUTOMATED STRUCTURE EVALUATION OF OPIATE ALKALOIDS
KLOPMAN, G; MACINA, OT; SIMON, EJ; MILLER, JM
1986 JAN ;27(3-4):299-308, Journal of molecular structure. Theochem
— id: 41615, year: 1986, vol: 27, page: 299, stat: Journal Article,

Progress in the characterization of the opioid receptor subtypes: peptides as probes. Future directions
Simon EJ
1986 ;70:155-174, NIDA research monograph series
— id: 63638, year: 1986, vol: 70, page: 155, stat: Journal Article,

Recent studies on opioid receptors: heterogeneity and purification
Simon EJ
1986 ;463:31-45, Annals of the New York Academy of Sciences
— id: 62263, year: 1986, vol: 463, page: 31, stat: Journal Article,

Antagonist-induced opiate receptor upregulation in cultures of fetal mouse spinal cord-ganglion explants
Tempel A; Crain SM; Peterson ER; Simon EJ; Zukin RS
1986 Mar;390(2):287-291, Brain research
Chronic exposure of fetal mouse spinal cord-ganglion explants to the opioid antagonist naloxone (10 microM, 7 days) produced a pronounced upregulation of mu opioid receptors. The antagonist action was stereospecific, as it was produced by (-)-, but not by (+)-naloxone, and was dose-dependent. Half-maximal naloxone-induced receptor upregulation occurred after two days; receptor density was maximal at 5 days. Exposure of the explant cultures to naloxone (10 microM) in the presence of the protein synthesis inhibitor, cycloheximide (1 microM; a concentration which blocks greater than 90% protein synthesis) resulted in receptor density changes that were similar to those observed in cultures exposed to naloxone alone. This finding suggests that antagonist-induced opiate receptor upregulation does not require the synthesis of new receptor molecules
— id: 63636, year: 1986, vol: 390, page: 287, stat: Journal Article,

Chloroacryloyl amides and alpha-methylenelactones from naltrexone, oxymorphone and fentanyl
Archer S; Michael J; Michael M; Simon EJ; Abdelhamid EM; Nelson WL; Koolpe GA
1985 Feb;5(4-6):395-398, Neuropeptides
A series of chloroacryloyl amides and alpha-methylenelactones were prepared from naltrexone and oxymorphone and some chloroacryloyl amides from fentanyl were prepared as potential Michael acceptors and irreversible ligands. The relative rates of Michael additions of p-methoxybenzenethiol to the double bonds were measured in an NMR spectrometer. The IC50's in rat brain homogenates and the irreversible binding to rat brain membranes were determined. In the methylene-lactone series, it was found that both the alpha and beta isomers derived from naltrexone and oxymorphone were excellent Michael acceptors, but only the beta isomers were more active in the opioid binding assays. The beta isomer derived from naltrexone was an irreversible ligand whereas the oxymorphone analogue was active only in the presence of 100 mM NaCl. In the chloroacryloyl series, only the alpha-chloroacryloyl amide derived from beta naltrexamine proved to be an irreversible binding ligand in the absence of NaCl. It was an excellent Michael acceptor. Under the conditions of our experiments, beta-FNA was a poor Michael acceptor and did not behave as an irreversible ligand in rat membranes
— id: 63645, year: 1985, vol: 5, page: 395, stat: Journal Article,

Hybromet: a ligand for purifying opioid receptors
Archer S; Michael J; Osei-Gyimah P; Seyed-Mozaffari A; Zukin RS; Maneckjee R; Simon EJ; Gioannini TL
1985 Dec;28(12):1950-1953, Journal of medicinal chemistry
Condensation of the Grignard reagent derive from 2-[4-(allyloxy)phenyl]ethyl bromide (4b) with 7 alpha-acetyl-6,14-endo-ethenotetrahydrothebaine (5) furnished the (R) tertiary carbinol, 7, which upon methoxymercuration followed by treatment with the KBr gave the bromomercurio compound 10 (Hybromet). The corresponding N-cyclopropylmethyl analogue, 11, was prepared also. The bromomercurio compound, 1, and the mercaptobenzothiazole derivative, 3, gave allyl phenyl ether when treated with BAL at room temperature. Similar treatment of 10 with BAL gave 7 in high yield. Binding studies using rat brain homogenates indicated that 7, 13, and 14 have moderately high affinities for mu rather than delta binding sites. Although much weaker, 10 showed preferential mu binding also. These results along with the fact that 10 reacted smoothly with sulfhydryl groups suggest that Hybromet would be a suitable ligand for use in affinity chromatography
— id: 62219, year: 1985, vol: 28, page: 1950, stat: Journal Article,

Relative affinities of the quaternary narcotic antagonist, N-methyl levallorphan (SR 58002), for different types of opioid receptors
Bianchetti A; Dragonetti M; Giudice A; Tarantino A; Ferrarese N; Manara L; Appelmans N; Simon EJ
1985 Feb;5(4-6):379-382, Neuropeptides
The relative affinities for different subtypes of opioid receptors (mu, kappa and delta) of the peripheral narcotic antagonist N-methyl levallorphan (SR 58002) have been studied in two in vitro smooth muscle systems (guinea-pig ileum and rabbit vas deferens) and by binding studies (guinea-pig brain and cerebellum membranes) using selective tritiated ligands. All the evidence obtained indicates that SR 58002 is a pure antagonist with relative affinity for mu receptors vs kappa and delta superior to that of the parent tertiary compound, levallorphan
— id: 62270, year: 1985, vol: 5, page: 379, stat: Journal Article,

Diphenhydramine potentiates narcotic but not endogenous opioid analgesia
Carr KD; Hiller JM; Simon EJ
1985 Feb;5(4-6):411-414, Neuropeptides
The analgesic effect of morphine in rats, as reflected in elevated thresholds for tail shock induced vocalizations, was markedly potentiated by the antihistamine, diphenhydramine. Intrinsic to the behavioral test paradigm employed are stressors which mobilize endogenous opioid activity as verified by the hyperalgesic effect of naloxone. Diphenhydramine failed to potentiate the analgesic effect of such endogenous opioid activity. The potentiating effect of antihistamines may therefore be mediated by mechanisms whose influence is restricted to systemically administered opiates
— id: 63644, year: 1985, vol: 5, page: 411, stat: Journal Article,

N-(3-Fluoropropyl)-N-normetazocine, a potentially useful opiate antagonist for opiate receptor studies with positron emission tomography (PET)
Feliu AL; Holland MJ; Carr KD; Fowler JS; Simon EJ
1985 Sep;49(3):323-336, Research communications in chemical pathology & pharmacology
A new fluorinated derivative of N-propylnormetazocine, N-(3-fluoropropyl)-N-normetazocine (1) was synthesized. 1 was similar to the unfluorinated analog 3 in its ability to compete with (3H)-naltrexone for binding sites in rat brain membranes and its potency in antagonizing morphine analgesia in rats. Competition of both compounds against (3H)-naltrexone was little affected by the presence of sodium chloride, a characteristic frequently exhibited by opiate antagonists. Morphine analgesia in rats was measured by suppression of locomotion and vocalization responses to footshock. The ability of 1 to antagonize morphine analgesia in rats was similar to that of 3. Neither 1 nor 3 showed any evidence of agonist activity in rats at doses as high as 1.0 mg/kg (the highest dose tested). These results suggest that 1, labeled with 18F, may be useful for in vivo studies of the opiate receptor using positron emission tomography (PET)
— id: 62115, year: 1985, vol: 49, page: 323, stat: Journal Article,

Purification of an active opioid-binding protein from bovine striatum
Gioannini TL; Howard AD; Hiller JM; Simon EJ
1985 Dec 5;260(28):15117-15121, Journal of biological chemistry
We report the purification to apparent homogeneity of an active opioid-binding protein solubilized from bovine striatal membranes. The purification was accomplished in two steps: affinity chromatography on beta-naltrexylethylenediamine (NED)-CH-Sepharose 4B followed by lectin affinity chromatography on wheat germ agglutinin-agarose. The ligand affinity-purified fraction exhibits stereospecific and saturable binding of opiates and is heat-sensitive. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of the NED-purified material gave 6-8 bands by silver staining or autoradiography of radioiodinated material. Under nondenaturing conditions, the NED-purified material elutes in a molecular mass range between 300 and 350 kDa from gel exclusion chromatography on Ultrogel AcA-34. The specific activity of the affinity-purified fraction (800-1500 pmol/mg protein) is enriched 4000 to 7000-fold over that of the membrane-bound or unpurified soluble receptor. Further purification (10-20-fold) is achieved by chromatography of the NED eluate on wheat germ agglutinin-agarose. The eluted fraction shows a single protein (65 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified material is an acidic glycoprotein with a pI of 6.0-6.3 and binds opiates with a specific activity (12,000-15,000 pmol/mg) that is 65,000 to 75,000-fold greater (theoretical, 77,000-fold) than that of the membrane-bound or crude soluble receptors
— id: 63641, year: 1985, vol: 260, page: 15117, stat: Journal Article,

Covalent labeling of opioid receptors with radioiodinated human beta-endorphin. Identification of binding site subunit
Howard AD; de La Baume S; Gioannini TL; Hiller JM; Simon EJ
1985 Sep 5;260(19):10833-10839, Journal of biological chemistry
125I-beta-Endorphin (human) binds with high affinity, specificity, and saturability to rat brain and neuroblastoma X glioma hybrid cell (NG 108-15) membranes. Dissociation constants and binding capacities were obtained from Scatchard plots and are 2 nM and 0.62 pmol/mg of protein for rat whole brain and 6 nM and 0.8 pmol/mg of protein for NG 108-15 cells. Results from competition experiments also indicate that this ligand interacts with high affinity with both mu and delta opioid binding sites, with a slight preference for mu sites, while exhibiting low affinity at kappa sites. We have demonstrated that human 125I-beta-endorphin is a useful probe for the investigation of the subunit structure of opioid receptors. The specific cross-linking of this ligand has revealed the presence of four reproducible bands or areas after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography at 65, 53, 38, and 25 kDa. All labeled bands seem to be opioid receptor related since they are eliminated when binding is carried out in an excess of various opiates. The evidence we have obtained using rat whole brain (delta congruent to mu), rat thalamus (largely mu), bovine frontal cortex (delta:mu congruent to 2:1), and NG 108-15 cells (delta) demonstrates that different labeling patterns are obtained when mu and delta binding sites are cross-linked. The pattern obtained on sodium dodecyl sulfate-polyacrylamide gel electrophoresis from cross-linked mu sites contains a major (heavily labeled) component of 65 kDa and a minor component of 38 kDa, while patterns from delta sites contain a major labeled component of 53 kDa. This 53-kDa band appears clearly in extracts from NG 108-15 cells and bovine frontal cortex, while in rat whole brain a diffusely labeled region is present between 55 and 41 kDa. In addition, NG 108-15 cells also display a minor labeled component at 25 kDa. The relationship of the minor bands to the major bands is not clear
— id: 63642, year: 1985, vol: 260, page: 10833, stat: Journal Article,

COVALENT LABELING OF OPIOID RECEPTORS WITH RADIOIODINATED HUMAN BETA-ENDORPHIN - IDENTIFICATION OF BINDING-SITE SUBUNITS
Howard, AD; Delabaume, S; Hiller, JM; Simon, EJ
1985 ;44(3):481-481, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 30781, year: 1985, vol: 44, page: 481, stat: Journal Article,

An opiate receptor-associated aminopeptidase that degrades enkephalins
Hui KS; Gioannini T; Hui M; Simon EJ; Lajtha A
1985 Aug;10(8):1047-1058, Neurochemical research
During the purification of opiate receptor by affinity chromatography on wheat germ agglutinin-agarose, an aminopeptidase is coeluted with the receptor. Virtually all of both the enzyme and the receptor is retained on the hydroxylapatite column. The aminopeptidase functions optimally at neutral pH and is activated by Mn2+. The enzyme is sensitive to dithiothreitol, is inhibited by amastatin and bestatin, and is insensitive to puromycin. The enzyme seems to be linked to the receptor, since its activity is enhanced by D-Ala2-Met-enkephalinamide or naltrexone. The properties of this aminopeptidase indicate that it is distinct from neutral arylamidase, leucine-aminopeptidase, aminopeptidases A and B, brain acidic aminopeptidase, and the membrane aminoenkephalinase that we purified recently (4)
— id: 60406, year: 1985, vol: 10, page: 1047, stat: Journal Article,

Characterization of specific binding sites for [3H](d)-N-allylnormetazocine in rat brain membranes
Itzhak Y; Hiller JM; Simon EJ
1985 Jan;27(1):46-52, Molecular pharmacology
Binding of [3H](d)-N-allylnormetazocine ([3H](d)-NANM) to rat brain membranes is stereospecific, reversible, and saturable (Bmax = 260 fmol/mg of protein) and manifests moderately high affinity (Kd = 20 nM). The rank order of potency among opioidbenzomorphans and phencyclidine (PCP) analogs for competition for [3H](d)-NANM-binding sites is as follows: (d)-NANM = PCP-3-OH greater than (d)-cyclazocine greater than N-ethylphenylcyclohexylamine greater than PCP greater than (l)-cyclazocine = dextrorphan greater than (d/l)-ethylketocyclazocine greater than (d/l)-bremazocine greater than (1)-NANM greater than 1-phenylcyclohexylamine greater than levorphanol. Other opioid ligands, relatively selective for each of the types of opioid binding sites other than sigma, such as morphine (mu), H-Tyr-D-Ala(Me)Phe-NH-CH2-OH (mu), D-Ala2-D-Leu5-enkephalin (delta), tifluadom (kappa), and U 50488 (kappa) as well as etorphine and naloxone were all unable to compete with [3H](d)-NANM for specific binding even at a concentration of 1 microM. Regional distribution studies of [3H](d)-NANM-binding sites show high density in the hippocampus, thalamus, hypothalamus, and amygdala and low density in cerebellum and nonfrontal neocortex membranes of the rat brain. These binding sites are very sensitive to protein-modifying enzymes and reagents such as trypsin and N-ethylmaleimide and to heat denaturation. These results provide direct biochemical evidence for the existence of distinct (d)-NANM-binding sites in rat brain. In addition, this study supports the view that PCP and several of its analogues and the dextrorotatory isomers of psychotomimetic benzomorphans may act at a common recognition site in rat central nervous system
— id: 63646, year: 1985, vol: 27, page: 46, stat: Journal Article,

Opioid agonists and antagonists. 6-Desoxy-6-substituted lactone, epoxide, and glycidate ester derivatives of naltrexone and oxymorphone
Koolpe GA; Nelson WL; Gioannini TL; Angel L; Appelmans N; Simon EJ
1985 Jul;28(7):949-957, Journal of medicinal chemistry
Synthesis and opioid radioreceptor assay data on analogues closely related to 6-desoxy-6-spiro-alpha-methylene-gamma-lactone 5a, a compound with irreversible activity in this assay, are reported. Saturated lactones (7a,b), endocyclic alpha, beta-unsaturated gamma-lactones (8a,b and 9a), and 6 alpha,7 alpha-fused alpha-methylene-gamma-lactones (10a and 11a) were prepared. Related 6-desoxy-6-methylene 6 beta- and 6 alpha-oxides (12a,b and 13a) and glycidate esters 14a,b and 15a,b were also prepared with use of naltrexone (1a) and oxymorphone (1b) as starting material. Compounds in the N-cyclopropylmethyl (N-CPM) series were more potent than those in the N-Me series in displacing [3H]naltrexone in the opioid radioreceptor assay, usually by 2-16-fold in the absence of Na ion. The most potent N-CPM analogues were epoxides 12a and 13a and glycidate esters 14a and 15a, showing IC50's of 2-6 nM, similar to that of 5a. Of the N-Me analogues, 6 beta-oxide 12b was most active, with an IC50 of 8 nM in the absence of Na ion. For the N-CPM analogues, the Na ion ratios were generally less than 1, with two exceptions. The N-Me analogues showed expected larger Na ion effects of 7 or greater. None of the lactone analogues had irreversible effects when preincubated in the rat brain membrane preparation, even at 37 degrees C for 30 min, i.e., washing restored [3H]naltrexone binding to control levels. These results clearly show that the alpha-methylene-gamma-lactone moiety of 5a is required for irreversible effects, consistent with it serving as a conjugate addition acceptor of a nucleophilic group from a ligand at or near the receptor. The epoxides and glycidate esters also had no irreversible activity, indicating more electrophilic functional groups are needed and/or these electrophiles are not properly aligned to react with nucleophilic groups at or near the opioid receptor
— id: 63643, year: 1985, vol: 28, page: 949, stat: Journal Article,

INTERACTIONS OF ACRYLOYL AMIDE DERIVATIVES OF NALTREXONE WITH OPIOID RECEPTORS
ABDELHAMID, EE; MICHAEL, MA; MICHAEL, J; ARCHER, S; SIMON, EJ
1984 ;43(3):584-584, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 41008, year: 1984, vol: 43, page: 584, stat: Journal Article,

Differential sensitivity of major types of opioid binding sites to U.V. irradiation
Aucelio JG; Hiller JM; Gioannini T; Simon EJ
1984 Dec;5(1-3):141-144, Neuropeptides
The three major types of opioid binding sites exhibited differential sensitivity to inactivation by ultraviolet irradiation. The order of sensitivity was delta greater than mu greater than kappa. Two separate rates of inactivation by U.V. light were observed for each type, an initial fast rate and a secondary slow rate. Addition of EDTA or EGTA to the buffer medium decreased only the initial fast rate of inactivation. The photosensitive tryptophan and tyrosine moieties have been shown to be photolyzed in a two step manner in a number of protein systems. It is suggested that the differential sensitivity of the multiple opioid binding sites may reflect either differing amino acid composition or differences in tertiary structure
— id: 63649, year: 1984, vol: 5, page: 141, stat: Journal Article,

Analgesic effects of ethylketocyclazocine and morphine in rat and toad
Carr KD; Aleman DO; Holland MJ; Simon EJ
1984 Aug 27;35(9):997-1003, Life sciences
We have previously found rat and toad (Bufo marinus) brain to contain inverse ratios of benzomorphan-preferring (kappa/sigma) and morphine-preferring (mu) opioid receptor types. The aim of the present study was to compare in vivo pharmacologic activity of a benzomorphan, ethylketocyclazocine (EKC) and morphine sulfate (MS) in rat and toad. Footshock intensity thresholds for eliciting locomotion were determined and dose-response curves for EKC and MS analgesia were obtained. Drugs were injected subcutaneously. In rats (high mu, low kappa in brain), both compounds produced analgesia and displayed similar sensitivity to naloxone antagonism. The analgesic effects of EKC and MS may, therefore, be mediated by a common receptor type (mu) in this pain test in rats. In toads (high kappa, low mu in brain), MS produced naloxone-reversible analgesia at doses 20-fold higher than were effective in rats. Toads did not display EKC analgesia at doses below those producing motor impairment. Moreover, 50-fold higher doses were required to produce such impairment in toads. Thirty minutes following subcutaneous injection of 3H-EKC, similar concentrations were found in rat and toad brain. Uptake into brain is probably not a factor in the behavioral resistance of toads to EKC
— id: 63650, year: 1984, vol: 35, page: 997, stat: Journal Article,

Potentiation of reward by hunger is opioid mediated
Carr KD; Simon EJ
1984 Apr 16;297(2):369-373, Brain research
In tests of frequency threshold for brain stimulation-induced feeding, naloxone (s.c.) did not affect the first in a brief series of threshold estimates but elevated subsequent estimates progressively. It was demonstrated that neither the time-course of drug action nor any cumulative disruptive effect of brain stimulation itself, accounts for the progressive elevation of threshold. Self-stimulation in 'feeding' electrodes was therefore studied, in combination with hunger manipulations, to inferentially evaluate naloxone's effect on feeding mechanisms. Results suggest naloxone's anoretic effect does not reflect heightened responsiveness of a satiety mechanism. Reversal by naloxone of the potentiating effect of hunger on self-stimulation, however, suggests the anoretic effect is due to blockade of an opioid process associated with hunger that otherwise enhances the reward value of food
— id: 63651, year: 1984, vol: 297, page: 369, stat: Journal Article,

Development of Met-enkephalin immunoreactivity in organotypic explants of fetal mouse spinal cord and attached dorsal root ganglia
Chalazonitis A; Groth J; Hiller JM; Simon EJ; Crain SM
1984 Feb;314(2):183-189, Brain research
Radioimmunoassays of methionine-enkephalin (Met-Enk) in organotypic cultures of 13-day fetal mouse spinal cord explants with attached dorsal root ganglia (DRG) demonstrate a progressive development of immunoreactivity (IR) during 5 weeks in vitro. Met-Enk IR in these cultures increased to levels observed in adult rodent spinal cord. most of the Met-Enk IR assays were made on cord explants excised from cord-DRG cultures. In smaller numbers of assays performed on entire DRG-cord cultures or on cord cultured in the absence of DRGs, similar levels of Met-Enk IR were obtained. Thus most of the Met-Enk IR appeared to be located within the cord tissue. No Met-Enk IR was detected in DRGs cultured in the absence of cord. In contrast, low levels of Met-Enk IR were present in about 50% of the assays of DRGs cultured attached to the cord. Since these assays included the neuritic outgrowths of the cultures, our data do not preclude possible contamination by Met-Enk immunoreactive cord neurites that may have aberrantly projected into the outgrowth zones. Nevertheless, the data raise the possibility of a trophic influence of cord tissue on the development of Met-Enk IR in DRG neurons. The development of Met-Enk IR in cord regions of cord-DRG explants extends previous binding assays demonstrating development of opiate receptors in these cultures and provides further support to electrophysiological analyses suggesting tonic opioid inhibitory networks in these explants
— id: 63655, year: 1984, vol: 314, page: 183, stat: Journal Article,

Affinity chromatography of solubilized opioid binding sites using CH-Sepharose modified with a new naltrexone derivative
Gioannini TL; Howard A; Hiller JM; Simon EJ
1984 Mar 15;119(2):624-629, Biochemical & biophysical research communications
An affinity gel containing a newly synthesized derivative of naltrexone, beta-naltrexyl-6-ethylenediamine (NED), was used to purify opioid binding sites by 300-450-fold. Binding sites solubilized from brains of toad, rat and cow using digitonin in the presence of 0.5 M NaCl are retained by the gel and can be eluted with naloxone (1-3 microM) in yields of 20-25%. The biospecificity of the interaction of opioid binding sites with modified beads is supported by the following: 1) unmodified beads do not retain the binding sites, 2) binding sites prebound with an opioid are not retained, 3) dilution of NED gels with unmodified Sepharose progressively reduced efficiency of retention and 4) specific receptor ligands elute binding sites retained on the NED gels
— id: 63652, year: 1984, vol: 119, page: 624, stat: Journal Article,

PARTIAL-PURIFICATION OF SOLUBILIZED OPIOID BINDING-SITES ON A NOVEL AFFINITY MATRIX
GIOANNINI, TL; HOWARD, A; HILLER, JM; SIMON, EJ
1984 ;43(3):542-542, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 41005, year: 1984, vol: 43, page: 542, stat: Journal Article,

Characterization of the selective inhibition of the delta subclass of opioid binding sites by alcohols
Hiller JM; Angel LM; Simon EJ
1984 Mar;25(2):249-255, Molecular pharmacology
We recently reported that ethanol and other aliphatic alcohols exert a selective inhibition on the binding of enkephalins to delta opioid binding sites. We report here a more detailed investigation of the characteristics of this inhibition. Opioid binding sites of the kappa subtype are similar to mu opioid binding sites in their relative insensitivity to inhibition by aliphatic alcohols. Scatchard analysis of saturation data of enkephalin binding showed that inhibition is the result of a decrease in affinity. Results of kinetic experiments demonstrated that the inhibition can be entirely accounted for by an increase in the dissociation rate of the ligand-receptor complex. The presence of sodium ions in the incubation medium and raising the temperature of incubation exacerbate the inhibitory effectiveness of alcohols. The order of potency among structural isomers of alcohols for inhibition of delta receptor binding is as follows: straight-chain primary greater than isoprimary greater than secondary greater than tertiary. The order of inhibitory potency of the aliphatic alcohols tested correlates well with their ability to disorder the cell membrane lipid bilayer. It is suggested that this is a probable mechanism by which alcohols inhibit binding to delta opioid binding sites
— id: 63653, year: 1984, vol: 25, page: 249, stat: Journal Article,

Etorphine pharmacokinetics in the rat: experimental data and mathematical model
Holland MJ; Simon EJ
1984 Dec;5(1-3):65-68, Neuropeptides
Rats were injected i.v. with 3H-etorphine (200 ng/Kg). At least 85% of the dose was cleared from the blood in the first 2 min. Blood levels continued to fall slowly from about 5% of the administered dose after 15 min to less than 2% after 3 hours. Although more than 15% of the dose was found in the liver and kidney after 15 min, labeled material did not further accumulate in these organs, but decreased to about 3% after 3 hours. The concentration of labeled material (dpm/mg tissue) in cerebellum was less than half that attained in other brain regions at early time points, probably reflecting the low number of opiate receptors in this region. After 2 hours, however, there was little difference between cerebellum and other brain regions. The highest brain concentrations observed were at the earliest time point examined (7 min). An open four compartment kinetic model was constructed to fit the data for etorphine concentrations in (i) plasma, (ii) cerebellum, and (iii) brain (excluding cerebellum). The model has 3 spatial compartments: plasma, brain, and all tissues other than brain. Etorphine in brain occupies either of 2 functional compartments: one representing receptor-bound ligand and the other, the sum of free and nonspecifically bound ligand. The dissociation rate constant for etorphine in vivo obtained by fitting model equations to data was 0.06 min-1, similar to that obtained in vitro in the presence of 150 mM sodium ion
— id: 63647, year: 1984, vol: 5, page: 65, stat: Journal Article,

MATHEMATICAL-MODEL FOR ETORPHINE PHARMACOKINETICS IN THE RAT
HOLLAND, MJC; SIMON, EJ
1984 ;43(3):750-750, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 41016, year: 1984, vol: 43, page: 750, stat: Journal Article,

Effect of digitonin on the binding of opiate agonists and antagonists to membrane-bound and soluble opioid binding sites
Itzhak Y; Hiller JM; Gioannini TL; Simon EJ
1984 Jan 23;291(2):309-315, Brain research
Treatment of rat or toad brain membranes with low concentrations of digitonin (0.01-0.1%) inhibits the binding of opioids to their receptors. Moreover, the binding of agonists is inhibited to a greater extent than that of antagonists. Inhibition of antagonist binding is completely and specifically reversed by sodium ions (200 mM) while agonist binding is not. The binding of opiates to toad brain membrane is significantly less sensitive to digitonin than the binding to rat brain membranes. The present results furnish an explanation for our previous findings, i.e. good yield of binding to (digitonin/NaCl) solubilized binding sites from rat brain can only be obtained with labeled opiate antagonists. Furthermore, they also explain why good yields of binding to the soluble opioid binding sites from toad brain can be obtained in the absence of sodium, while high concentrations of NaCl are required for mammalian brain, such as rat
— id: 63656, year: 1984, vol: 291, page: 309, stat: Journal Article,

Solubilization and characterization of kappa opioid binding sites from guinea pig cerebellum
Itzhak Y; Hiller JM; Simon EJ
1984 Dec;5(1-3):201-204, Neuropeptides
Solubilization of opioid binding sites from guinea pig cerebellum by digitonin, in the absence and presence of NaCl, resulted in very similar yields (25-30%) of [3H]bremazocine binding. Saturation curves of [3H]bremazocine binding give linear Scatchard plots for both soluble and membrane-bound binding sites yielding similar Kd's and Bmax's. Soluble kappa sites seem to resemble closely their membrane-bound counterparts and retain high affinity and selectivity for various kappa opioid ligands. The apparent molecular weight of soluble kappa sites is ca. 4 X 10(5). Results from this study, along with our previous findings with toad and guinea pig brain, indicate that kappa sites (unlike mu and delta) can be solubilized in good yield by digitonin even in the absence of NaCl. This supports the hypothesis that kappa sites may represent molecular species different from those of mu and delta sites
— id: 63648, year: 1984, vol: 5, page: 201, stat: Journal Article,

Solubilization and characterization of mu, delta, and kappa opioid binding sites from guinea pig brain: physical separation of kappa receptors
Itzhak Y; Hiller JM; Simon EJ
1984 Jul;81(13):4217-4221, Proceedings of the National Academy of Sciences of the United States of America
Sucrose density gradient centrifugation of digitonin-solubilized opioid binding sites from guinea pig brain and cerebellum was carried out. Centrifugation of extracts of whole brain into a gradient devoid of sodium and low in digitonin revealed the presence of two well-separated peaks of opioid binding activity. Peak A was shown to have the binding characteristics of kappa sites, whereas peak B seems to be a mixture of mu and delta sites. When extracts of guinea pig cerebellum were treated in the same manner, a single peak of binding activity was obtained that coincided with peak A from guinea pig brain and exhibited the characteristics of kappa binding sites. All three sites closely resemble their membrane-bound counterparts, retaining good affinity and selectivity for their appropriate ligands. The apparent sedimentation coefficients (S20,w) of the digitonin-solubilized binding sites present in the two peaks are 19 s for peak A and 34-39 s for peak B, and the estimated apparent molecular weights are 400,000 for kappa sites and 750,000-875,000 for the mixture of mu and delta sites. Our results suggest that kappa sites constitute separate molecular entities from mu and delta sites
— id: 63186, year: 1984, vol: 81, page: 4217, stat: Journal Article,

A novel phencyclidine analog interacts selectively with mu opioid receptors
Itzhak Y; Simon EJ
1984 Aug;230(2):383-386, Journal of pharmacology & experimental therapeutics
A new potent analgesic drug, 1-(1-phenylcyclohexyl)-4-phenyl-4-piperidinol (PCP-4-Ph-4-OH), derived from phencyclidine was tested for its interactions with different types of opioid receptors. The antinociceptive effect of PCP-4-Ph-4-OH in the mouse writhing test (ED50 = 0.3 mg/kg) is reversed by low doses of naloxone (pA2 = 6.98). The potency of PCP-4-Ph-OH in the inhibition of the electrically induced contractions of the guinea-pig ileum (IC50 = 17 nM) is 8-fold higher than that in the mouse vas deferens preparation (IC50 = 130 nM). The concentration of naloxone required to double the IC50 (Ke) of PCP-4-Ph-4-OH is 1.5 to 1.9 nM in both preparations. In opioid radioreceptor assays, PCP-4-Ph-4-OH displays 60- to-300 fold higher affinity for the [3H] dihydromorphine (mu) and D-[3H]Ala2-MePhe-Gly-ol5-enkephalin (mu) binding sites than for D-[3H]Ala2-D-Leu5-enkephalin (delta) sites in rat brain and [3H]bremazocine (kappa) sites in guinea-pig cerebellar membrane preparations. These results suggest that PCP-4-Ph-4-OH interacts with high affinity and selectivity with mu opioid receptors
— id: 62229, year: 1984, vol: 230, page: 383, stat: Journal Article,

PCP-4-PH-4-OH SELECTIVELY INTERACTS WITH MU OPIOID RECEPTORS
ITZHAK, Y; SIMON, EJ
1984 ;43(4):953-953, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 40998, year: 1984, vol: 43, page: 953, stat: Journal Article,

Diastereomeric 6-desoxy-6-spiro-alpha-methylene-gamma-butyrolactone derivatives of naltrexone and oxymorphone. Selective irreversible inhibition of naltrexone binding in an opioid receptor preparation by a conformationally restricted michael acceptor ligand
Koolpe GA; Nelson WL; Gioannini TL; Angel L; Simon EJ
1984 Dec;27(12):1718-1723, Journal of medicinal chemistry
The diastereomeric 6-desoxy-6-spiro-alpha-methylene-gamma-butyrolactone derivatives of naltrexone (4a and 5a) and of oxymorphone (4b and 5b) were prepared from their parent ketones. Diastereomers 4a and 4b were obtained from the 3,14-diacetate derivatives of naltrexone (6a) and oxymorphone (6b) by reaction with the Reformatsky reagent prepared from methyl alpha-(bromomethyl)acrylate. Deacetylation with methanol completed the synthesis. Diastereomers 5a and 5b were obtained from oxiranes 8a and 8b, respectively. The oxiranes were allowed to react with the sodium salt of ethyl acetoacetate, followed by methenation and deprotection to complete the synthesis of 5a and 5b, respectively. Compound 5a was the most potent agent tested in competition against [3H]naltrexone in the opioid radioreceptor assay. At a concentration of 5 nM this compound produced a 50% inhibition of binding. The majority of this inhibition (30%) was irreversible, i.e., it remained even after extensive washing of the membrane preparation in the presence and absence of Na+. Naloxone protected against this irreversible effect. The data suggest a receptor nucleophile, perhaps a sulfhydryl group, is located where it can add to the alpha, beta-unsaturated carbonyl system of 5a
— id: 62221, year: 1984, vol: 27, page: 1718, stat: Journal Article,

Recent studies on opioid receptors: heterogeneity and isolation (the Nathan B. Eddy Memorial Award lecture)
Simon EJ
1984 Mar;49:5-13, NIDA research monograph series
— id: 63654, year: 1984, vol: 49, page: 5, stat: Journal Article,

SOLUBILIZATION OF KAPPA-OPIOID RECEPTORS FROM GUINEA-PIG CEREBELLUM
SIMON, EJ; ITZHAK, Y
1984 ;43(3):542-542, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 41003, year: 1984, vol: 43, page: 542, stat: Journal Article,

Quaternary derivatives of narcotic antagonists: stereochemical requirements at the chiral nitrogen for in vitro and in vivo activity
Bianchetti A; Nisato D; Sacilotto R; Dragonetti M; Picerno N; Tarantino A; Manara L; Angel LM; Simon EJ
1983 ;33 Suppl 1:415-418, Life sciences
We have studied three pairs of diastereoisomers of quaternary narcotic antagonists and their parent tertiary amines, levallorphan, nalorphine and naloxone, to see how configuration about the chiral nitrogen affects in vitro and in vivo activity. In each series only the diastereoisomer obtained by methylation of the N-allyl substituted tertiary amine (N-methyl diast.) was potent in displacing 3H-naltrexone from rat brain membranes (Ki 10(-8) - 10(-7)M) and as pure morphine antagonist in the guinea-pig ileum (Ki 10(-8)-10(-7)M). Conversely, diastereoisomers obtained by reacting N-methyl substituted tertiary amines with allyl halide (N-allyl diast.) did not displace 3H-naltrexone, up to 10(-6)M, and had negligible antagonist activity and slight agonist action in the guinea-pig ileum. In vivo findings (charcoal meal transit test in mice) were generally consistent with those in vitro. Thus only the N-methyl but not the N-allyl diast. inhibited morphine constipation and behaved as pure antagonists
— id: 63660, year: 1983, vol: 33 Suppl 1, page: 415, stat: Journal Article,

Effects of naloxone and its quarternary analogue on stimulation-induced feeding
Carr KD; Simon EJ
1983 Jan;22(1):127-130, Neuropharmacology
Feeding was induced in rats by electrical stimulation in the lateral hypothalamus. Naloxone (0.2 and 1.0 mg/kg) produced a dose-related elevation of the frequency threshold for stimulation-induced feeding while quarternary naloxone (2.0 and 10.0 mg/kg) had no effect. Since quarternary naloxone does not readily penetrate the blood-brain barrier, we conclude that the opiate receptors at which naloxone exerts its anorectic action are located in the brain rather than in potential peripheral tissues such as gastrointestinal tract, pancreas or adrenal medulla. The threshold-elevating effect of naloxone only became marked after rats had engaged in one or two 5-sec bouts of feeding. The effect continued to increase following each subsequent bout of feeding. Naloxone therefore appears to inhibit feeding by interacting with post-ingestive factors
— id: 63657, year: 1983, vol: 22, page: 127, stat: Journal Article,

The role of opioids in feeding and reward elicited by lateral hypothalamic electrical stimulation
Carr KD; Simon EJ
1983 ;33 Suppl 1:563-566, Life sciences
We have previously shown that feeding induced by electrical stimulation in the lateral hypothalamus of rats is inhibited by naloxone but not its quaternary analogue. In the present study, effects of morphine and loperamide -an opiate that does not pass the blood-brain barrier- were examined. Loperamide inhibited stimulation-induced feeding; reversal of this effect by quaternary naloxone confirmed the peripheral site of action. A low dose of morphine (1.25 mg/kg) facilitated feeding but higher doses were inhibitory. An inhibitory dose of morphine became facilitory, however, when preceded by quaternary naloxone. It therefore appears that central opioid activity promotes ingestive behavior while peripheral activity inhibits ingestion. To evaluate the function served by the central facilitory process, we exploited the relation that exists between feeding and self-stimulation elicited through a common electrode. It was found that potentiation of self-stimulation by food deprivation is blocked by naloxone. It is concluded that endogenous opioid activity may promote feeding by enhancing the reward value of food as a function of hunger
— id: 63658, year: 1983, vol: 33 Suppl 1, page: 563, stat: Journal Article,

Evidence from opiate binding studies that heroin acts through its metabolites
Inturrisi CE; Schultz M; Shin S; Umans JG; Angel L; Simon EJ
1983 ;33 Suppl 1:773-776, Life sciences
The relative affinity to opiate receptors of heroin, 6-acetylmorphine and morphine was estimated by determining their ability to displace specifically bound 3H-naltrexone from rat brain opiate binding sites. In vitro hydrolysis of heroin to 6-acetylmorphine was monitored in the binding assay filtrate by use of a quantitative HPLC procedure. The rate of heroin hydrolysis was significantly slower at 0 degrees C than at 37 degrees C. The displacement of 1 nM 3H-naltrexone by unlabeled ligand at concentrations ranging from 7 to 500 nM was measured at 0 degrees C for 120 minutes, yielding IC50 values of heroin = 483 nM, 6-acetylmorphine = 73 nM and morphine = 53 nM. When the binding data for heroin were recalculated to include the displacement that could be attributed to the 6-acetylmorphine derived from heroin degradation during the incubation, all of the apparent heroin binding was accounted for by the 6-acetylmorphine. These results are consistent with previous reports of the low binding affinity of morphine congeners (e.g., codeine) that lack a free phenolic 3-hydroxyl group and support the view that heroin is a prodrug which serves to determine the distribution of its intrinsically active metabolites, 6-acetylmorphine and morphine
— id: 63659, year: 1983, vol: 33 Suppl 1, page: 773, stat: Journal Article,

Evidence for the solubilization of multiple opioid binding sites from mammalian brain
Itzhak Y; Hiller JM; Gioannini TL; Simon EJ
1983 ;33 Suppl 1:191-194, Life sciences
Good yields of 3H-opioid agonist binding in solution have been obtained following fractionation of brain membrane extracts on sucrose density gradients. The presence of multiple opioid binding sites was demonstrated for extracts from rat and guinea pig brain. Fractionation of solubilized material from guinea pig brain resulted in the separation of the peak of 3H-bremazocine binding (in the presence of DAGO and DADL) from the peaks of binding of tritiated mu and delta agonists. These results suggest that the kappa binding site may represent a separate molecular species from mu and delta opioid binding sites
— id: 63661, year: 1983, vol: 33 Suppl 1, page: 191, stat: Journal Article,

Medial thalamic lesions reduce the aversion-gating action of lateral hypothalamic stimulation
Carr KD; Bonnet KA; Simon EJ
1982 Aug 26;246(2):342-346, Brain research
— id: 63666, year: 1982, vol: 246, page: 342, stat: Journal Article,

Mu and kappa opioid agonists elevate brain stimulation threshold for escape by inhibiting aversion
Carr KD; Bonnet KA; Simon EJ
1982 Aug 12;245(2):389-393, Brain research
Rats were trained to press a lever to escape electrical stimulation of the nucleus reticularis gigantocellularis and to obtain stimulation of the lateral hypothalamus. Morphine sulfate and ethylketocyclazocine (EKC) both elevated the intensity of stimulation required to sustain escape at doses which did not affect self-stimulation. Parallel dose-response lines were obtained for the two opioid agonists but the effect of EKC was more resistant to naloxone antagonism. These results suggest that both mu-and chi-sub-types of opiate receptor mediate the inhibition of supraspinally-elicited aversion
— id: 63667, year: 1982, vol: 245, page: 389, stat: Journal Article,

Exposure to 4-aminopyridine prevents depressant effects of opiates on sensory-evoked dorsal-horn network responses in spinal cord cultures
Crain SM; Crain B; Peterson ER; Hiller JM; Simon EJ
1982 Jul 19;31(3):235-240, Life sciences
The depressant effects of morphine (0.1-1 microM) on sensory-evoked dorsal-horn network responses in explants of mouse spinal cord with attached dorsal root ganglia (DRGs) were rapidly restored after addition of 4-aminopyridine (4-AP; 0.1 mM) and major components of these cord responses were stably maintained in the presence of the opiate. Moreover, prior exposure of cord-DRG explants to 0.1 mM 4-AP prevented the depressant effects of 0.1 microM morphine on DRG-evoked dorsal-horn responses, and the effects of 1-10 microM morphine were at least partly antagonized. Increased Ca++ levels (5 microM) attenuated the depression of dorsal horn responses by 1-10 micro M morphine and these effects of Ca++ were greatly enhanced in the presence of 4-AP--in some cultures, concentrations of morphine as high as 100 micro M were strongly antagonized during test periods up to 2 hours. Receptor assays showed that 0.1 mM 4-AP +/- 5 mM Ca++ had no effect on stereospecific opiate binding, indicating that the antagonist actions of these agents in our cultures do not occur at the level of the opiate receptor. The relevance of our in vitro studies of 4-AP antagonism of opiate-depressant effects on sensory-evoked dorsal-horn network responses for analyses of problems in opiate analgesia has been strengthened by a recent report demonstrating that 4-AP does, in fact, reverse morphine analgesia in rats, as determined by tail flick tests
— id: 63668, year: 1982, vol: 31, page: 235, stat: Journal Article,

Lectin binding of solubilized opiate receptors: evidence for their glycoprotein nature
Gioannini T; Foucaud B; Hiller JM; Hatten ME; Simon EJ
1982 Apr 14;105(3):1128-1134, Biochemical & biophysical research communications
— id: 62148, year: 1982, vol: 105, page: 1128, stat: Journal Article,

Solubilization in good yield of active opiate binding sites from mammalian brain
Gioannini TL; Howells RD; Hiller JM; Simon EJ
1982 Sep 20-27;31(12-13):1315-1318, Life sciences
Active opiate binding sites have been solubilized from mammalian brain cell membranes. The presence of 0.5-0.1 M NaCl during treatment of membranes from rat brain, human frontal cortex, and bovine corpus striatum with glycodeoxycholate or digitonin resulted in the extraction of active opiate binding sites in yields ranging up to 43%. The criteria for solubility of the sites were their inability to sediment at 10(5) x g after 2 hr and their apparent molecular weight of 3- 4 x 10(5) as determined by gel filtration. The receptors in solution resemble the membrane-bound sites with respect to saturability, stereo-specificity, sensitivity to heat and reagents, and high affinity for opioid ligands. The interaction of solubilized sites with immobilized lectins was used to demonstrate the glycoprotein nature of the opiate receptor. Soluble receptors from all species studied were retained by wheat germ agglutinin(WGA)-agarose and could be specifically eluted with N-acetylglucosamine. No retention of solubilized material was observed with eight other lectins examined, including horseshoe crab lectin, a sialic acid specific agglutinin. The receptor protein eluted from WGA columns was enriched 25-50-fold over the crude soluble fraction
— id: 63663, year: 1982, vol: 31, page: 1315, stat: Journal Article,

THE OPIATE RECEPTOR IS A GLYCOPROTEIN - EVIDENCE FROM LECTIN AFFINITY-CHROMATOGRAPHY
Gioannini, T; Foucaud, B; Hiller, JM; Hatten, MB; Simon, EJ
1982 ;41(4):1031-1031, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 30459, year: 1982, vol: 41, page: 1031, stat: Journal Article,

Solubilization and characterization of active opiate binding sites from mammalian brain
Howells RD; Gioannini TL; Hiller JM; Simon EJ
1982 Sep;222(3):629-634, Journal of pharmacology & experimental therapeutics
Active binding sites have been solubilized from cell membranes derived from mammalian brain. High affinity, stereospecific binding to soluble sites was demonstrable when membranes from rat brain, human frontal cortex and bovine corpus striatum were treated with digitonin or glycodeoxycholate, provided that the binding assay was conducted at 25 degrees C or below and in the presence of 50 to 100 mM NaCl. The yield of solubilized binding sites extracted from brain cell membranes was increased substantially (up to 43% yield from bovine striatum) when membranes were treated with detergent solutions containing 0.5 to 1.0 M NaCl. This effect was not observed when LiCl, KCl or (NH4)2SO4 were substituted for NaCl. Evidence for the solubility of the binding sites was provided by two criteria: nonsedimentation after 2 hr of centrifugation at 10(5) X g and an apparent molecular weight of 3 to 4 X 10(5) as determined by gel filtration
— id: 63665, year: 1982, vol: 222, page: 629, stat: Journal Article,

SOLUBILIZATION OF ACTIVE OPIATE BINDING-SITES FROM MAMMALIAN BRAIN
Howells, RD; Gioannini, TL; Hiller, JM; Simon, EJ
1982 ;41(5):1635-1635, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 30454, year: 1982, vol: 41, page: 1635, stat: Journal Article,

Multiple opiate binding sites in human brain regions: evidence for kappa and sigma sites
Itzhak Y; Bonnet KA; Groth J; Hiller JM; Simon EJ
1982 Sep 20-27;31(12-13):1363-1366, Life sciences
— id: 63662, year: 1982, vol: 31, page: 1363, stat: Journal Article,

Potential affinity labels for the opiate receptor based on fentanyl and related compounds
Maryanoff BE; Simon EJ; Gioannini T; Gorissen H
1982 Aug;25(8):913-919, Journal of medicinal chemistry
Derivatives of fentanyl, 3-methylfentanyl, sufentanil, and lofentanil, possessing chemo- or photoaffinity functionalities, were synthesized as potential affinity reagents for the opiate receptor. Opiate receptor binding constants (IC50) were determined in competition experiments with [3H]naloxone and [3H]naltrexone. Affinity-labeling experiments were generally unsuccessful, although some irreversible attachment was achieved with alpha-diazoamide 17 and aryl azide 23
— id: 62220, year: 1982, vol: 25, page: 913, stat: Journal Article,

Binding characteristics of mu and kappa agonists in rat brain subcellular fractions
Monferini E; Adler MW; Simon EJ
1982 Sep 20-27;31(12-13):1295-1298, Life sciences
Scatchard analysis of 3H-dihydromorphine (3H-DHM) binding to rat brain subcellular fractions gave a curvilinear plot in the microsomal (P3) and a linear plot in the mitochondrial (P2) fraction, respectively. In contrast, plots of 3H-ethylketocyclazocine (3H-EK) binding were linear in the P3 and curvilinear in the P2 fraction. No differences were seen in the potency of morphine and ketazocine in displacing either 3H-DHM or 3H-EK in the P2 fraction. In the P3 fraction, however, morphine was more potent than ketazocine in displacing 3H-DHM, but the reverse was true when 3H-EK was used as the ligand. Isolation of the P3 fraction may facilitate the demonstration of a kappa receptor in the rat brain
— id: 63664, year: 1982, vol: 31, page: 1295, stat: Journal Article,

Inactivation and solubilization of opiate receptors by phospholipases A2
Ruegg UT; Cuenoud S; Fulpius BW; Simon EJ
1982 Mar 8;685(3):241-248, Biochimica & biophysica acta
(1) As previously shown, stereospecific binding of opiates to membrane bound receptors is inhibited by treatment with small amounts of phospholipase A2 from Vipera russelli. This effect is quantified and compared with the enzymes from the venoms of Naja Naja siamensis, Apis Mellifica and from porcine pancreas. All enzymes are equally effective. The inhibition is due to partial phospholipid hydrolysis leading to inactivation of membrane-bound receptor. (2) Bee venom phospholipase A2 together with the synergistically acting peptide, melittin, causes receptor solubilization up to 80% of preformed receptor-ligand complex can be solubilized in this manner. (3) Lysophosphatidylcholine, a product of phospholipid hydrolysis, solubilizes performed receptor-ligand complex to a similar extent. Several other detergents were tested for their ability to solubilize receptor-ligand complex. Digitonin appears to be most effective in solubilizing such a complex
— id: 62152, year: 1982, vol: 685, page: 241, stat: Journal Article,

Opiate receptors and opioid peptides: an overview
Simon EJ
1982 ;398:327-339, Annals of the New York Academy of Sciences
— id: 62262, year: 1982, vol: 398, page: 327, stat: Journal Article,

The nature of opiate receptors in toad brain
Simon EJ; Hiller JM; Groth J; Itzhak Y; Holland MJ; Beck SG
1982 Sep 20-27;31(12-13):1367-1370, Life sciences
— id: 62237, year: 1982, vol: 31, page: 1367, stat: Journal Article,

Recent work on opiate receptors: heterogeneity and solubilization
Simon EJ; Hiller JM; Ruegg UT; Gioannini T; Howells RD; Groth J; Angel L; Bonnet KA
1982 ;33:311-319, Advances in biochemical psychopharmacology
— id: 62260, year: 1982, vol: 33, page: 311, stat: Journal Article,

Opiate receptor heterogeneity in human brain regions
Bonnet KA; Groth J; Gioannini T; Cortes M; Simon EJ
1981 Sep 28;221(2):437-440, Brain research
— id: 62161, year: 1981, vol: 221, page: 437, stat: Journal Article,

Multiple opiate receptors: alcohol selectively inhibits binding to delta receptors
Hiller JM; Angel LM; Simon EJ
1981 Oct 23;214(4519):468-469, Science
The addition of ethanol or other aliphatic alcohols to rat brain membranes strongly inhibits binding of enkephalins at concentrations at which little inhibition of opiate alkaloids is seen. Inhibition is reversible, and potency increases with chain length of the alcohol. The results suggest that delta receptors are considerably more sensitive to alcohols than mu receptors. This is the first demonstration of selective inhibition of one of the postulated classes of opiate receptors by a reagent that is not a ligand for the receptor
— id: 62256, year: 1981, vol: 214, page: 468, stat: Journal Article,

Characterization of phospholipase A inhibition of stereospecific opiate binding and its reversal by bovine serum albumin
Lin HK; Holland MJ; Simon EJ
1981 Jan;216(1):149-155, Journal of pharmacology & experimental therapeutics
Opiate receptor binding is inhibited by phospholipase A from some sources, whereas the enzyme from other sources is inactive even at much higher concentrations. Evidence is presented that an active enzymatic site is required for inhibition and that the degree of inhibition seems to correlate with the extent of phospholipolysis. The inhibition is reversed almost completely by treatment with 0.5 to 1% bovine serum albumin, even up to 90% inhibition by phospholipase. As more enzyme is added or incubation time is increased, the extent of reversal diminishes. Based on our evidence, the most likely explanation of these results is that the inhibition of opiate binding activity by phospholipase A is due to the toxicity of the products of phospholipolysis and that bovine serum albumin reverses the inhibition by removing these products from the membranes, thereby restoring the active conformation of the receptors
— id: 63669, year: 1981, vol: 216, page: 149, stat: Journal Article,

Presence of leucine-enkephalin in organotypic explants of fetal mouse spinal cord
Naftchi NE; Abrahams SJ; Crain SM; Peterson ER; Hiller JM; Simon EJ
1981 ;2 Suppl 1:57-60, Peptides
Spinal cord explants with attached dorsal root ganglia (DRGs), from 14-day fetal mice were fixed at 1-3 weeks in vitro and incubated for leucine-enkephalin (LE) immunoreactivity by the peroxidase-anti-peroxidase (PAP) immunohistochemical method. Results show long processes with labeled varicosities seen more often in dorsal regions of the cord explants. Stained punctate bodies and varicosities were often seen close to large cells in these cultures, whereas no label was detected in neuronal perikarya. A prominent laminar array of stained punctate bodies was noted in one cord explant, concentric with the perimeter of the explant. No LE label was detected in the neuritic outgrowths from the cord-DRG explants, whereas high levels of opiate receptors develop in these outgrowths, primarily on the DRG neurites, by 1-2 weeks in culture. The results indicate the presence of LE in explants of fetal mouse spinal cord with attached DRGs and offer an in vitro model system in which the onset and development of peptidergic neurons can be studied as they form functional cellular interrelationships with neurons bearing opioid and monoaminergic receptors in these organotypic cultures
— id: 63670, year: 1981, vol: 2 Suppl 1, page: 57, stat: Journal Article,

Characterization and partial purification of solubilized active opiate receptors from toad brain
Ruegg UT; Cuenod S; Hiller JM; Gioannini T; Howells RD; Simon EJ
1981 Jul;78(7):4635-4638, Proceedings of the National Academy of Sciences of the United States of America
Opiate receptors have been solubilized from toad brain membranes in active form by using digitonin. Between 40% and 50% of the stereospecific binding activity present in toad brain membranes is recoverable in the ultracentrifugal supernatant of digitonin extracts. Binding of opiates to the solubilized receptor is enhanced 4- to 5-fold by decreasing digitonin concentration to 0.1% or less prior to binding. The solubilized receptor is similar to the membrane-bound receptor in its affinity for various ligands and its sensitivity to heat, trypsin, and N-ethylmaleimide. Moreover, the sodium effect seen in membrane-bound receptor is retained in the solubilized preparation. Both membrane-bound and soluble toad receptors show weak binding of enkephalins, suggesting that they are predominantly of the mu type. The solubilized opiate receptor has an approximate molecular weight of 350,000-400,000. Purification of up to 20-fold has been achieved by gel filtration on Sepharose CL-6B
— id: 62247, year: 1981, vol: 78, page: 4635, stat: Journal Article,

Effect of the position of the phenolic group in morphinans on their affinity for opiate receptor binding
Simon LD; Simon FR; Mohasci E; Berger L; Simon EJ
1981 Jun 15;28(24):2769-2772, Life sciences
— id: 62236, year: 1981, vol: 28, page: 2769, stat: Journal Article,

OPIATE RECEPTORS - SOME RECENT DEVELOPMENTS
SIMON, EJ
1981 ;2(6):155-158, Trends in pharmacological science
— id: 40330, year: 1981, vol: 2, page: 155, stat: Journal Article,

Endorphins, opiate receptors and their evolving biology
Smith JR; Simon EJ
1981 ;11:87-126, Pathobiology annual
— id: 63671, year: 1981, vol: 11, page: 87, stat: Journal Article,

Advances in endogenous and exogenous opioids : proceedings of the International Narcotic Research Conference
Takagi, Hiroshi; Simon, Eric J
Tokyo : Kodansha, 1981,
— id: 1763, year: 1981, vol: , page: , stat: ,

Specific, high affinity [3H]ethylketocyclazocine binding in rat central nervous system: lack of evidence for kappa receptors
Hiller JM; Simon EJ
1980 Sep;214(3):516-519, Journal of pharmacology & experimental therapeutics
The binding properties and distribution of the tritiated benzomorphan, [3H]ethylketocyclazocine, were studied in rat central nervous system (CNS). Specific binding is saturable and represents 75 to 90% of total binding. Scatchard analysis is consistent with the existence of two classes of binding sites with Kd values of 0.5 and 10.5 nM, respectively. Ethylketocyclazocine binding is increased in the presence of sodium chloride. This characteristic resembles that of opiate antagonists rather than that of other agonists. The distribution of ligands. The IC50 values of various opioid agonists and antagonists for competition with [3H]ethylketocyclazocine correlate well with their IC50 values for competition with [3H]naloxone. This evidence does not lend support to the existence of a separate kappa receptor in rat CNS
— id: 62227, year: 1980, vol: 214, page: 516, stat: Journal Article,

Opiate binding sites in the retina: properties and distribution
Howells RD; Groth J; Hiller JM; Simon EJ
1980 Oct;215(1):60-64, Journal of pharmacology & experimental therapeutics
The presence of opiate binding sites in rat retina was confirmed and their properties and distribution were investigated. Etorphine, naloxone and methionine enkephalin exhibit high affinity, saturable binding to retinal membrane preparations. Scatchard analysis of the binding data yielded linear plots for each ligand. The P1 subcellular fraction contains the greatest density of sites per milligram of protein. The response of the binding of all ligands to sodium ions was similar in the retina to that observed in the brain. Competition experiments using naloxone and methionine enkephalin indicated that a homogeneous class of binding sites exists in the rat retina. Opiate binding sites were also demonstrated in the retina of cow, toad and skate. Methionine enkephalin-like immunoreactivity was not clearly detectable in rat retina but was present in toad retina. The physiological role of the opiate binding sites in the retina remains to be elucidated
— id: 63673, year: 1980, vol: 215, page: 60, stat: Journal Article,

Benzodiazepine binding in chicken retina and its interaction with gamma-aminobutyric acid
Howells RD; Simon EJ
1980 Oct 3;67(1):133-137, European journal of pharmacology
Chicken retina contains saturable, stereoselective high affinity binding sites for benzodiazepines. The density of binding sites in chicken retina exceeds that found in rat and cow retina. GABA and muscimol increase specific 3H-flunitrazepam binding in the chicken retina in a dose-dependent manner. This effect is reversed by bicuculline methiodide. The enhancement of specific binding caused by GABA was shown to be due to an increase in the affinity of flunitrazepam, while the number of binding sites remained unchanged
— id: 63672, year: 1980, vol: 67, page: 133, stat: Journal Article,

Radioautography of binding of tritiated diprenorphine to opiate receptors in the rat
Pearson J; Brandeis L; Simon E; Hiller J
1980 Mar 31;26(13):1047-1052, Life sciences
— id: 62232, year: 1980, vol: 26, page: 1047, stat: Journal Article,

Solubilization of an active opiate receptor from Bufo marinus
Ruegg UT; Hiller JM; Simon EJ
1980 Jun 27;64(4):367-368, European journal of pharmacology
— id: 62174, year: 1980, vol: 64, page: 367, stat: Journal Article,

STUDY OF AGENTS EFFECTIVE IN SOLUBILIZING OPIATE RECEPTORS
RUEGG, UT; SIMON, EJ; HILLER, JM; FULPIUS, BW
1980 ;36(6):731-731, Experientia
— id: 98658, year: 1980, vol: 36, page: 731, stat: Journal Article,

Opiate receptors and their implications for drug addiction
Simon EJ
1980 Mar;30:303-308, NIDA research monograph series
— id: 63674, year: 1980, vol: 30, page: 303, stat: Journal Article,

Recent studies on interaction between opioid peptides and their receptors
Simon EJ; Bonnet KA; Crain SM; Groth J; Hiller JM; Smith JR
1980 ;22:335-346, Advances in biochemical psychopharmacology
— id: 63675, year: 1980, vol: 22, page: 335, stat: Journal Article,

Selective protection of stereospecific enkephalin and opiate binding against inactivation by N-ethylmaleimide: evidence for two classes of opiate receptors
Smith JR; Simon EJ
1980 Jan;77(1):281-284, Proceedings of the National Academy of Sciences of the United States of America
Stereospecific binding of 3H-labeled [D-Ala2,D-Leu5]enkephalin is irreversibly inactivated by the sulfhydryl group alkylating agent N-ethylmaleimide. This inactivation, like that of opiate binding, exhibits pseudo-first-order kinetics with a half-inactivation time of 10-12 min. The presence of opiates or enkephalins during incubation with N-ethylmaleimide provides good protection. Ouantitative studies of protection demonstrate that naltrexone and morphine are 20 and 8 times, respectively, more effective in protecting the binding of [3H]naltrexone than that of [3H]enkephalin. [D-Ala2,Leu]Enkephalin and [D-Ala2,Met]enkephalin, however, are more effective (7 and 30 times, respectively) for the protection of 3H-labeled [D-Ala2,D-Leu5]enkephalin binding. These results provide strong evidence for the existence of two classes of opiate receptor in rat brain
— id: 62240, year: 1980, vol: 77, page: 281, stat: Journal Article,

Development of tolerance to opiates and opioid peptides in organotypic cultures of mouse spinal cord
Crain SM; Crain B; Finnigan T; Simon EJ
1979 Nov 19;25(21):1797-1802, Life sciences
— id: 63677, year: 1979, vol: 25, page: 1797, stat: Journal Article,

Selective depression by opiates and opioid peptides of sensory evoked dorsal horn network responses in organized fetal mouse spinal cord cultures
Crain SM; Crain B; Peterson ER; Simon EJ
1979 ;22:375-378, Proceedings of the Western Pharmacology Society
— id: 63679, year: 1979, vol: 22, page: 375, stat: Journal Article,

3H-ethylketocyclazocine binding: lack of evidence for a separate kappa receptor in rats CNS
Hiller JM; Simon EJ
1979 Dec 20;60(4):389-390, European journal of pharmacology
— id: 63168, year: 1979, vol: 60, page: 389, stat: Journal Article,

Benzodiazepine binding sites are present in retina
Howells RD; Hiller JM; Simon EJ
1979 Dec 10-17;25(24-25):2131-2136, Life sciences
— id: 63676, year: 1979, vol: 25, page: 2131, stat: Journal Article,

In vitro studies of opiate receptors
Simon EJ
1979 ;20:31-51, Advances in biochemical psychopharmacology
— id: 63680, year: 1979, vol: 20, page: 31, stat: Journal Article,

Studies on membrane-bound opiate receptors
Simon EJ
1979 ;27:51-62, Progress in clinical & biological research
— id: 63681, year: 1979, vol: 27, page: 51, stat: Journal Article,

Opioid activity of synthetic and naturally occurring enkephalin peptides
Simon EJ; Bonnet KA; Hiller JM; Rieman MW; Merrifield RB
1979 Nov 15;28(22):3333-3337, Biochemical pharmacology
— id: 63678, year: 1979, vol: 28, page: 3333, stat: Journal Article,

Selective depression by opioid peptides of sensory-evoked dorsal-horn network responses in organized spinal cord cultures
Crain SM; Crain B; Peterson ER; Simon EJ
1978 Nov 17;157(1):196-201, Brain research
— id: 63682, year: 1978, vol: 157, page: 196, stat: Journal Article,

SELECTIVE DEPRESSION BY ENDORPHINS OF SENSORY-EVOKED SYNAPTIC NETWORK DISCHARGES IN DORSAL HORN OF SPINAL-CORD CULTURES
CRAIN, SM; CRAIN, B; PETERSON, ER; SIMON, EJ
1978 ;37(3):237-237, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 98686, year: 1978, vol: 37, page: 237, stat: Journal Article,

Opiate receptors in cultures of fetal mouse dorsal root ganglia (DRG) and spinal cord: predominance in DRG neurites
Hiller JM; Simon EJ; Crain SM; Peterson ER
1978 Apr 28;145(2):396-400, Brain research
— id: 62160, year: 1978, vol: 145, page: 396, stat: Journal Article,

DISTRIBUTION OF OPIATE RECEPTORS IN ORGANIZED CULTURES OF FETAL MOUSE SPINAL-CORD AND DORSAL ROOT-GANGLI
Hiller, JM; Simon, EJ; Crain, SM; Peterson, ER
1978 ;37(3):238-238, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 29949, year: 1978, vol: 37, page: 238, stat: Journal Article,

Phospholipase A inhibition of opiate receptor binding can be reversed by albumin
Lin HK; Simon EJ
1978 Jan 26;271(5643):383-384, Nature
— id: 62251, year: 1978, vol: 271, page: 383, stat: Journal Article,

EFFECT OF PHOSPHOLIPASES A ON OPIATE RECEPTOR ACTIVITY
Lin, HK; Simon, EJ
1978 ;176(SEP):126-126, Abstracts of papers (American Chemical Society)
— id: 29886, year: 1978, vol: 176, page: 126, stat: Journal Article,

REVERSAL BY BOVINE SERUM-ALBUMIN OF PHOSPHOLIPASE-A INHIBITION OF OPIATE RECEPTOR-BINDING
Lin, HK; Simon, EJ
1978 ;37(3):238-238, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 29839, year: 1978, vol: 37, page: 238, stat: Journal Article,

Effect of morphine analogues on chemotaxis in Escherichia coli
Persky-Brosh S; Young JR; Holland MJ; Simon EJ
1978 Jul;107(1):53-58, Journal of general microbiology
Pretreatment of Escherichia coli w3110 with levorphanol, a morphine analogue, reduced chemotaxis to serine, aspartic acid and galactose. This decreased chemotaxis was not due to decreased viability or motility. Pretreatment with 1.1 mM-levorphanol for 1 h, followed by washing to remove the drug prior to determination of chemotaxis, inhibited chemotaxis to each of the attractants by at least 80%. Pretreatment with dextrorphan, the enantiomorph of levorphanol, or levallorphan, the N-allyl analogue of levorphanol, resulted in a similar inhibition of chemotaxis. Reversal of the inhibition produced by pretreatment with levorphanol required a period of growth of at least one generation time
— id: 63683, year: 1978, vol: 107, page: 53, stat: Journal Article,

[Opiate receptors and endorphins at the central nervous system level]
Simon EJ
1978 ;19(5):379-387, Annales de l'anesthesiologie francaise
Four years ago, sterospecific sites for the bending of opiates were discovered within the brain of animals and the human being. All of the properties of these sites are in conformity with the proposition that they are pharmacological receptors which have long been postulated for these drugs. The binding of morphine or of one of its derivatives to these sites should result in chemical or physical reactions leading to well known pharmacological responses. These reactions following the binding of drugs to the receptors are not yet known, but there is some evidence that cyclical nucleotides play a role. The affinity of a whole series of morphine derivatives, agonists and atagonists, is well correlated with their pharmacological effectiveness. In the presence of sodium salts, antagonists become more strongly bound and agonists less strongly than in the absence of sodium. The evidence is presented. This is explained by an equilibrium between two formations of the receptor: one characteristic of the absence of sodium and one of its presence. Receptors are found in the nervous system of all vertebrates and their distribution has been studied in the human brain. The regions with the highest concentration of receptors are those of the limbic system. A high level exists also in the 'substantia gelatinosa' of the spinal cord, which is involved in the passage of painful messages. Study of the function of morphine receptors has led to the isolation, in animal brain, of a number of peptides with morphine properties named endorphines. The first two endorphines isolated were pentapeptides named encephalins. The properties of endorphines from the subject of several lecture in this course
— id: 62145, year: 1978, vol: 19, page: 379, stat: Journal Article,

In vitro studies on opiate receptors and their ligands
Simon EJ; Hiller JM
1978 Feb;37(2):141-146, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 62180, year: 1978, vol: 37, page: 141, stat: Journal Article,

The opiate receptors
Simon EJ; Hiller JM
1978 ;18:371-394, Annual review of pharmacology & toxicology
— id: 62295, year: 1978, vol: 18, page: 371, stat: Journal Article,

CITATION CLASSIC - PREPARATION OF S-SUCCINYL COENZYME-A
Simon, EJ
1978 ;85(19):11-11, Current contents
— id: 29691, year: 1978, vol: 85, page: 11, stat: Journal Article,

Selective opiate depression of sensory-evoked synaptic networks in dorsal horn regions of spinal cord cultures
Crain SM; Peterson ER; Crain B; Simon EJ
1977 Sep 9;133(1):162-166, Brain research
— id: 63686, year: 1977, vol: 133, page: 162, stat: Journal Article,

Analysis of electrical noise in turtle cones
Lamb TD; Simon EJ
1977 Nov;272(2):435-468, Journal of physiology
— id: 63685, year: 1977, vol: 272, page: 435, stat: Journal Article,

Opiate receptors in the central nervous system
Simon EJ
1977 ;4:33-69, Current developments in psychopharmacology
— id: 63687, year: 1977, vol: 4, page: 33, stat: Journal Article,

Receptor affinity and pharmacological potency of a series of narcotic analgesic, anti-diarrheal and neuroleptic drugs
Stahl KD; van Bever W; Janssen P; Simon EJ
1977 Dec 1;46(3):199-205, European journal of pharmacology
A series of 26 drugs was tested for in vitro binding to opiate receptors in the presence and absence of 0.1 M NaCl. The results were correlated with assays for in vivo pharmacological potency. Highly significant correlation was found between binding in the presence and absence of sodium ions and analgesic potency. For 10 drugs tested for anti-diarrheal potency significant correlation was observed with binding to brain opiate receptors when binding was carried out in sodium-containing medium. These data add support to the hypothesis that stereospecific opiate binding sites are pharmacological receptors which mediate analgesia and anti-diarrheal action. We found that neuroleptics can bind to opiate receptors with affinities in the micromolar range, in agreement with reports by others. The anti-diarrheal compound loperamide exhibits no significant central opiate effects but binds to opiate receptors from brain in vitro with high affinity. Evidency is presented suggesting that the lack of specific analgesic effect is the result of poor penetration through the blood--brain barrier. Our results lend further support to the similarity of opiate receptors in the brain and in the intestinal tract
— id: 63171, year: 1977, vol: 46, page: 199, stat: Journal Article,

The purification of antimorphine antibodies by affinity chromatography
Walker MC; Simon EJ
1977 Nov;203(2):360-364, Journal of pharmacology & experimental therapeutics
Affinity chromatography was employed successfully to purify extensively antimorphine antibodies produced in rabbits. Morphine succinylated at position 6 was attached to bovine serum albumin to make it immunogenic and to Sepharose beads for affinity chromatography. A crude gamma-globulin fraction of antimorphine serum, prepared by salt fractionation, was used for purification. After unbound gamma-globulin was washed off the column with phosphate-buffered saline, two populations of antimorphine antibodies were eluted in succession by two low pH buffers. Each of these two purified antibody fractions had an index of heterogeneity of approximately 1. Immunoelectrophoresis indicated that the antibodies were immunoglobulin G and that they formed a single precipitation band with antirabbit serum. The average association constants for morphine of the two purified antibody fractions were similar and ranged from 4.5 to 4.8 X 10(7) LITERS/MOL-1. A 67-fold purification of the antimorphine antibodies could be achieved by a single pass through an affinity column
— id: 63684, year: 1977, vol: 203, page: 360, stat: Journal Article,

Ontological development of opiate receptors in rodent brain
Clendeninn NJ; Petraitis M; Simon EJ
1976 Dec 10;118(1):157-160, Brain research
— id: 62159, year: 1976, vol: 118, page: 157, stat: Journal Article,

Power spectral measurements of noise in the turtle tetina [proceedings]
Lamb TD; Simon EJ
1976 Dec;263(1):103P-105P, Journal of physiology
— id: 63689, year: 1976, vol: 263, page: 103P, stat: Journal Article,

The relation between intercellular coupling and electrical noise in turtle photoreceptors
Lamb TD; Simon EJ
1976 Dec;263(2):257-286, Journal of physiology
1. Intracellular recordings from cones and rods in the retina of the turtle, Pseudemys scripta elegans, revealed that in darkness the cell voltage fluctuated spontaneously about its mean level. The fluctuations were reduced during bright steady illmination of the cell often to a level close to that obtained with the electrode outside the cell where the noise did not change significantly during illumination. 2. The magnitude of the intrinsic dark noise (voltage variance in darkness minus voltage variance in strong light) varied widely from cell to cell. In the noisiest cones it was about 0-4 mV2 while in quiet cones it was often as low as 0-01 mV2. The noise appeared radom and could be fitted by a Gaussian probability density function. 3. The spread of voltage in the network of coupled photoreceptors was estimated by measuring the spatial profile of the response to a brief flash of constant intensity moved across the retina. For a light stimulus in the form of a long narrow slit, the peak flash response usually decayed exponentially with displacement from the centred position. 4. For maximum responses less than about 5 mV in cones, the length constant of exponential decay, lambda, varied from less than 10 mum to greater than 35 mum, and the values obtained in opposite directions were often unequal. Background illumination did not significantly change lambda. In cells with extremely narrow spatial profiles, an exponential fit to the decay could not be made reliably. 5. Occasionally the spatial profiles had definite secondary peaks. In the most pronounced examples in a red-sensitive cone and in a rod the maxima were separated by about 20 and 50 mum respectively; for each, one peak was approximately as sharp as the optical stimulator while the second was broader. 6. Cones with short length constants displayed high dark noise while cones with long length constants were relatively quiet. 7. Three models of electrical coupling between cells were investigated: one based on a distributed network, one on a discrete square grid arrangement, and one on a discrete hexagonal array. Each model predicts a strong dependence of both noise and input resistance on length constant, and for tightly coupled cells each predicts that voltage variance is proportional to lambda-2. 8. The measured relationship between voltage variance and lambda in a large sample of cones was well described by both discrete models when the average cell spacing was taken to be approximately 15 mum. 9..
— id: 63688, year: 1976, vol: 263, page: 257, stat: Journal Article,

OPIATE RECEPTORS
Simon, EJ
1976 ;1(1):3-28, Neurochemical research
— id: 28791, year: 1976, vol: 1, page: 3, stat: Journal Article,

Inhibition by levorphanol and related drugs of amino acid transport by isolated membrane vesicles from Escherichia coli
Holland MJ; Simon EJ
1975 May;7(5):530-537, Antimicrobial agents & chemotherapy
— id: 63694, year: 1975, vol: 7, page: 530, stat: Journal Article,

Metabolism of polyamines in mouse neuroblastoma cells in culture: formation of GABA and putreanine
Kremzner LT; Hiller JM; Simon EJ
1975 Dec;25(6):889-894, Journal of neurochemistry
— id: 63690, year: 1975, vol: 25, page: 889, stat: Journal Article,

ANATOMIC LOCALIZATION OF NARCOTIC ANALGESIC BINDING IN BRAIN
Pearson, J; Hiller, J; Simon, E
1975 ;34(1):101-101, Journal of neuropathology & experimental neurology
— id: 28583, year: 1975, vol: 34, page: 101, stat: Journal Article,

Properties of centre-hyperpolarizing, red-sensitive bipolar cells in the turtle retina
Richter A; Simon EJ
1975 Jun;248(2):317-334, Journal of physiology
1. Responses of centre-hyperpolarizing, red-sensitive bipolar cells were studied by intracellular recording in the retina of the turtle, Pseudemys scripta elegans. The identity of these cells was confirmed by Procion Yellow marking. 2. Circles of light produced hyperpolarizing waves that were graded with intensity and could exceed -30mV in amplitude. The operating intensity range was similar to that of turtle cones. 3. Flashes in the form of an annulus evoked graded depolarizations which could be greater than 10 mV in the dark-adapted state or about 30mV when applied over central backgrounds. 4. Responses proportional to intensity were produced by dim circular stimuli. For radii less than about 200 mum these responses reached peak in approximately 120 msec and were invariant with respect to wave-length or area of illumination. Absolute flash sensitivity varied greatly from cell to cell but in the most sensitive cell encountered was about 460 muV photon(-1) um2. 5. Sensitivity of both bipolar cells and red-sensitive cones was enhanced progressively for enlargements of a circular flash up to 150-200 mum in radius. 6. Increasing the radius of a circle from 200 to 1250 mum caused a decrease of about 75% in bipolar cell sensitivity. This decrease was associated with a marked shortening of the response for all colours. The same enlargement decreased sensitivity of red-sensitive cones by approximately 20% and did not appreciably alter the time course of their response. These effects are attributed to impingement from type I red-sensitive horizontal cells because they have the requisite spatial and spectral properties. 7. Responses of a few bipolar cells were already shortened for 200 mum flashes; this property suggests impingement from type II horizontal cells. 8. For small circles the spectral sensitivity of the bipolar cells considered resembled closely that of red-sensitive cones or horizontal cells. Red backgrounds enhanced the relative sensitivity to green flashes suggesting that these bipolar cells receive input from red-sensitive members of double cones as well as single red-sensitive cones. 9. Steady depolarizing currents injected into bipolar cells decreased the response to either central or annular illumination; hyperpolarizing currents decreased the response to a central flash and increased the response to an annulus
— id: 63693, year: 1975, vol: 248, page: 317, stat: Journal Article,

Kinetics of opiate receptor inactivation by sulfhydryl reagents: evidence for conformational change in presence of sodium ions
Simon EJ; Groth J
1975 Jun;72(6):2404-2407, Proceedings of the National Academy of Sciences of the United States of America
The role of SH groups in opiate-receptor interactions has been further examined. In activation by N-ethylmaleimide of sterospecific opiate binding by rat brain membrane fractions follows pseudo-first order kinetics and exhibits strong temperature dependence. The kinetics indicate that alkylation of a single SH group suffices to block opiate binding. Considerable protection from SH group inactivation is observed when treatment with N-ethylmaleimide is carried out in the presence of an opiate or an antagonist, suggesting close proximity of the SH group to the opiate binding site. The rate of inactivation of receptor binding by N-ethylmaleimide is markedly slower in buffers containing 100 mM NaCl (t1/2 equals 30 plus or minus 1.4 min) than in sodium-free buffers (t1/2 equals 10 plus or minus 1.0 min). Since the rate of alkylation of model SH compounds is unaffected by sodium ions, this protection seems best explained by a conformational change in the receptors that renders the SH groups less accessible to alkylation. The rate of inactivation is not affected by K+, Rb+, or Cs+ and only slightly by Li+. This cation specificity as well as the concentration-response to Na+ are remarkably similar to those previously shown to lead to increased antagonist and decreased agonist binding. We suggest that the same conformational change is involved in the two phenomena
— id: 62243, year: 1975, vol: 72, page: 2404, stat: Journal Article,

Solubilization of a stereospecific opiate-macromolecular complex from rat brain
Simon EJ; Hiller JM; Edelman I
1975 Oct 24;190(4212):389-390, Science
A [3H]etorphine-macromolecular complex has been solubilized from rat brain synaptosomal fraction by extraction with the nonionic detergent Brij 36T. Stereospecificity of binding to this solubilized complex was demonstrated by the finding that radioactivity in the complex was virtually eliminated when binding had occurred in the presence of excess levorphanol, an active narcotic analgesic, while it was unaffected by its inactive enantiomorph dextrorphan. Bound radioactivity was dissociated by proteolytic enzymes, sulfhydryl reagents, and heat, suggesting the presence of protein. The bound solubilized macromolecular moiety may be the opiate receptor
— id: 63691, year: 1975, vol: 190, page: 389, stat: Journal Article,

Opiate receptors and their interactions with agnoists and antagonists
Simon EJ; Hiller JM; Edelman I; Groth J; Stahl KD
1975 Jun 15;16(12):1795-1800, Life sciences
— id: 62233, year: 1975, vol: 16, page: 1795, stat: Journal Article,

Further properties of stereospecific opiate binding sites in rat brain: on the nature of the sodium effect
Simon EJ; Hiller JM; Groth J; Edelman I
1975 Mar;192(3):531-537, Journal of pharmacology & experimental therapeutics
Addition of sodium salts has been reported to enhance stereospecific binding of opiate antagonists while reducing binding of agonists to rat brain homogenate. We have tested, in addition to sodium and potassium, a number of organic cations. Our results support the suggestion that the ability to enhace antagonist binding is not a general characteristic of cations or high ionic strength, but a property of sodium ions. We have shown that the increase in antagonist binding results from an enhancement of binding affinity and not from unmasking of new binding sites. The reduction in etorphine binding in the presence of sodium is due to a decrease in binding affinity. This decrease is largely accounted for by an acceleration in the dissociation rate, while the greater affinity of naltrexone binding appears to be due to an increase in rate of association. Our results are consistent with the hypothesis of a conformational change in opiate binding sites in the presence of sodium, transformed sites exhibiting greater affinity for antagonists and reduced affinity for agonists. Preheating of rat brain P2 fraction at 50 degrees C results in gradual inactivation of stereospecific binding, but an increase in naltrexone binding is consistently observed after heating at 50 degrees C for 2 to 3 minutes, even at optimal concentrations of sodium
— id: 63695, year: 1975, vol: 192, page: 531, stat: Journal Article,

Spontaneous voltage fluctuations in retinal cones and bipolar cells
Simon EJ; Lamb TD; Hodgkin AL
1975 Aug 21;256(5519):661-662, Nature
— id: 63692, year: 1975, vol: 256, page: 661, stat: Journal Article,

EVIDENCE FOR A CONFORMATIONAL CHANGE IN OPIATE RECEPTORS IN PRESENCE OF SODIUM
Simon, EJ; Groth, J
1975 ;34(3):713-713, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 28561, year: 1975, vol: 34, page: 713, stat: Journal Article,

STUDIES ON OPIATE RECEPTOR-SITES IN CENTRAL NERVOUS-SYSTEM
Simon, EJ; Hiller, JM
1975 ;51(10):1190-1190, Bulletin of the New York Academy of Medicine
— id: 28510, year: 1975, vol: 51, page: 1190, stat: Journal Article,

Effects of levorphanol on phospholipid metabolism in the giant axon of the squid
Dole WP; Simon EJ
1974 Jan;22(1):183-185, Journal of neurochemistry
— id: 63700, year: 1974, vol: 22, page: 183, stat: Journal Article,

Interactions leading to horizontal cell responses in the turtle retina
Fuortes MG; Simon EJ
1974 Jul;240(1):177-198, Journal of physiology
— id: 63697, year: 1974, vol: 240, page: 177, stat: Journal Article,

Electrical responses of double cones in the turtle retina
Richter A; Simon EJ
1974 Nov;242(3):673-683, Journal of physiology
— id: 63696, year: 1974, vol: 242, page: 673, stat: Journal Article,

Affinity chromatography of morphine and related drugs
Simon EJ
1974 ;34:619-623, Methods in enzymology
— id: 63699, year: 1974, vol: 34, page: 619, stat: Journal Article,

Feedback loop between cones and horizontal cells in the turtle retina
Simon EJ
1974 Apr;33(4):1078-1082, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 63698, year: 1974, vol: 33, page: 1078, stat: Journal Article,

OPIATE RECEPTORS IN HUMAN AND ANIMAL BRAIN
Simon, EJ
1974 ;5(7874):44-44, Journal de pharmacologie
— id: 28362, year: 1974, vol: 5, page: 44, stat: Journal Article,

Comparative studies on synaptosomes: uptake of (N-Me-3H)choline by synaptosomes from squid optic lobes
Dowdall MJ; Simon EJ
1973 Oct;21(4):969-982, Journal of neurochemistry
— id: 63703, year: 1973, vol: 21, page: 969, stat: Journal Article,

Colour-dependence of cone responses in the turtle retina
Fuortes MG; Schwartz EA; Simon EJ
1973 Oct;234(1):199-216, Journal of physiology
— id: 63702, year: 1973, vol: 234, page: 199, stat: Journal Article,

Distribution of stereospecific binding of the potent narcotic analgesic etorphine in the human brain: predominance in the limbic system
Hiller JM; Pearson J; Simon EJ
1973 Nov;6(3):1052-1062, Research communications in chemical pathology & pharmacology
— id: 63701, year: 1973, vol: 6, page: 1052, stat: Journal Article,

Inhibition by levorphanol of the induction of acetylcholinesterase in a mouse neuroblastoma cell line
Hiller JM; Simon EJ
1973 Jun;20(6):1789-1792, Journal of neurochemistry
— id: 63707, year: 1973, vol: 20, page: 1789, stat: Journal Article,

INHIBITION BY LEVORPHANOL OF PROLINE TRANSPORT BY ISOLATED MEMBRANE VESICLES FROM ESCHERICHIA-COLI
HOLLAND, MJC; SIMON, EJ
1973 ;32(3):600-&, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 39881, year: 1973, vol: 32, page: 600, stat: Journal Article,

POLYAMINE METABOLISM IN MOUSE NEUROBLASTOMA CELL-CULTURES
KREMZNER, LT; HILLER, JM; SIMON, EJ
1973 ;32(3):525-&, Federation Proceedings (Federation of American Societies for Experimental Biology)
— id: 39880, year: 1973, vol: 32, page: 525, stat: Journal Article,

Interaction of ribonucleic acid polymerase from Escherichia coli with deoxyribonucleic acid. Inhibition of ribonucleic acid synthesis by interaction of luteoskyrin with the transcription complex
Ruet A; Sentenac A; Simon EJ; Bouhet JC; Fromageot P
1973 Jun 5;12(12):2318-2324, Biochemistry
— id: 63706, year: 1973, vol: 12, page: 2318, stat: Journal Article,

In search of the opiate receptor
Simon EJ
1973 Sep;266(3):160-168, American journal of the medical sciences
— id: 62143, year: 1973, vol: 266, page: 160, stat: Journal Article,

Two types of luminosity horizontal cells in the retina of the turtle
Simon EJ
1973 Apr;230(1):199-211, Journal of physiology
— id: 63708, year: 1973, vol: 230, page: 199, stat: Journal Article,

Micropuncture study of the mechanism of endolymph production in the frog
Simon EJ; Hilding DA; Kashgarian M
1973 Jul;225(1):114-118, American journal of physiology
— id: 63705, year: 1973, vol: 225, page: 114, stat: Journal Article,

Stereospecific binding of the potent narcotic analgesic (3H) Etorphine to rat-brain homogenate
Simon EJ; Hiller JM; Edelman I
1973 Jul;70(7):1947-1949, Proceedings of the National Academy of Sciences of the United States of America
— id: 63704, year: 1973, vol: 70, page: 1947, stat: Journal Article,

The effect of levorphanol tartrate on ribonucleic acid synthesis in normal and regenerating rat liver
Becker FF; Rossman T; Reiss B; Simon EJ
1972 Jan;3(1):105-116, Research communications in chemical pathology & pharmacology
— id: 63710, year: 1972, vol: 3, page: 105, stat: Journal Article,

Coupling of a new, active morphine derivative to sepharose for affinity chromatography
Simon EJ; Dole WP; Hiller JM
1972 Jul;69(7):1835-1837, Proceedings of the National Academy of Sciences of the United States of America
— id: 63709, year: 1972, vol: 69, page: 1835, stat: Journal Article,

Effects of levorphanol on phospholipid metabolism and composition in Escherichia coli
Wurster, N; Elsbach, P; Rand, J; Simon, E J
1971 Nov 5;248(2):282-292, Biochimica & biophysica acta
— id: 41969, year: 1971, vol: 248, page: 282, stat: Journal Article,

The effects of the morphine analogue levorphanol on leukocytes. Metabolic effects at rest and during phagocytosis
Wurster, N; Elsbach, P; Simon, E J; Pettis, P; Lebow, S
1971 May;50(5):1091-1099, Journal of clinical investigation
— id: 41972, year: 1971, vol: 50, page: 1091, stat: Journal Article,

The effect of the morphine analog levorphanol on phagocytosing leukocytes. A morphologic study
Zucker-Franklin, D; Elsbach, P; Simon, E J
1971 Nov;25(5):415-421, Laboratory investigation
— id: 41970, year: 1971, vol: 25, page: 415, stat: Journal Article,

Reversible inhibition of RNA phage replication and macromolecular synthesis by levorphanol
Simon EJ; Garwes DJ; Rand J
1970 Sep 10;40(5):1134-1141, Biochemical & biophysical research communications
— id: 63712, year: 1970, vol: 40, page: 1134, stat: Journal Article,

Effects of narcotics on the giant axon of the squid
Simon EJ; Rosenberg P
1970 Jul;17(7):881-887, Journal of neurochemistry
— id: 63713, year: 1970, vol: 17, page: 881, stat: Journal Article,

Effect of levorphanol on putrescine transport in Escherichia coli
Simon EJ; Schapira L; Wurster N
1970 Nov;6(6):577-587, Molecular pharmacology
— id: 63711, year: 1970, vol: 6, page: 577, stat: Journal Article,

Inhibition of the synthesis of 5-S ribosomal RNA in Escherichia coli by levallorphan
Roschenthaler R; Devynck MA; Fromageot P; Simon EJ
1969 Jun 17;182(2):481-490, Biochimica & biophysica acta
— id: 63714, year: 1969, vol: 182, page: 481, stat: Journal Article,

Initiation of chains by RNA polymerase and the effects of inhibitors studied by a direct filtration technique
Sentenac A; Simon EJ; Fromageot P
1968 Jul 23;161(2):299-308, Biochimica & biophysica acta
— id: 63715, year: 1968, vol: 161, page: 299, stat: Journal Article,

Polyamines and inhibition of RNA synthesis in E. coli by levorphanol
Simon EJ; Cohen SS; Raina A
1966 Aug 12;24(3):482-488, Biochemical & biophysical research communications
— id: 63716, year: 1966, vol: 24, page: 482, stat: Journal Article,

The selective inhibition of ribosomal RNA synthesis in E. coli by 2,4-Dinitrophenol
Simon EJ; Van Praag D; Aronson FL
1966 Jan;2(1):43-49, Molecular pharmacology
— id: 63718, year: 1966, vol: 2, page: 43, stat: Journal Article,

Studies on the intracellular distribution and tissue binding of dihydromorphine-7,8-H3 in the rat
Van Praag D; Simon EJ
1966 May;122(1):6-11, Proceedings of the Society for Experimental Biology & Medicine
— id: 63717, year: 1966, vol: 122, page: 6, stat: Journal Article,

INHIBITION OF BACTERIAL GROWTH BY DRUGS OF THE MORPHINE SERIES
SIMON EJ
1964 May 1;144:543-544, Science
— id: 63720, year: 1964, vol: 144, page: 543, stat: Journal Article,

INHIBITION OF RNA SYNTHESIS IN ESCHERICHIA COLI BY LEVORPHANOL
SIMON EJ; VANPRAAG D
1964 May;51:877-883, Proceedings of the National Academy of Sciences of the United States of America
— id: 63721, year: 1964, vol: 51, page: 877, stat: Journal Article,

SELECTIVE INHIBITION OF SYNTHESIS OF RIBOSOMAL RNA IN ESCHERICHIA COLI BY LEVORPHANOL
SIMON EJ; VANPRAAG D
1964 Jun;51:1151-1158, Proceedings of the National Academy of Sciences of the United States of America
— id: 63719, year: 1964, vol: 51, page: 1151, stat: Journal Article,

Inhibition of synthesis of RNA in E. coli by the narcotic drug laevorphanol
SIMON EJ
1963 May 25;198:794-795, Nature
— id: 63722, year: 1963, vol: 198, page: 794, stat: Journal Article,

Turnover of muscle and liver proteins in mice with hereditary muscular dystrophy
SIMON EJ; GROSS CS; LESSELL IM
1962 Jan;96:41-46, Archives of biochemistry & biophysics. ABB
— id: 63723, year: 1962, vol: 96, page: 41, stat: Journal Article,

An impaired concentrating mechanism for amino acids in mutants of Escherichia coli resistant to L-canavanine and D-serine
SCHWARTZ JH; MAAS WK; SIMON EJ
1959 Apr;32:582-583, Biochimica & biophysica acta
— id: 63725, year: 1959, vol: 32, page: 582, stat: Journal Article,

In vitro effect of tocopherol metabolites on respiratory decline in dietary necrotic liver degeneration
SCHWARZ K; MERTZ W; SIMON EJ
1959 Apr;32:484-491, Biochimica & biophysica acta
— id: 63724, year: 1959, vol: 32, page: 484, stat: Journal Article,

The metabolism of vitamin E. II. Purification and characterization of urinary metabolites of alpha-tocopherol
EISENGART A; MILHORAT AT; SIMON EJ; SUNDHEIM L
1956 Aug;221(2):807-817, Journal of biological chemistry
— id: 63726, year: 1956, vol: 221, page: 807, stat: Journal Article,

The metabolism of vitamin E. I. The absorption and excretion of d-alpha-tocopheryl-5-methyl-C14-succinate
GROSS CS; MILHORAT AT; SIMON EJ
1956 Aug;221(2):797-805, Journal of biological chemistry
— id: 63727, year: 1956, vol: 221, page: 797, stat: Journal Article,