301
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Huang P, Kim S, Loew G. Development of a common 3D pharmacophore for delta-opioid recognition from peptides and non-peptides using a novel computer program. J Comput Aided Mol Des 1997; 11:21-8. [PMID: 9139108 DOI: 10.1023/a:1008067209563] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A unified three-dimensional (3D) pharmacophore for recognition of the delta-opioid receptor by families of structurally diverse delta-opioid ligands, including peptides and non-peptides, has been determined. An additional structural feature required for delta-selectivity was also characterized using a subset of these ligands that are highly selective for the delta-opioid receptor. To obtain these pharmacophores, we have used a recently developed computer program that performs systematic and automated comparisons of molecules to determine whether any common 3D relationships exist among candidate recognition moieties in high-affinity analogs. All the low-energy conformations of each ligand are included in these comparisons. The program developed should be applicable in general to molecular superimposition problems in rational drug design and to develop both 3D recognition and activation pharmacophores for any receptor for which high- and low-affinity analogs and agonists and antagonists have been identified.
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Affiliation(s)
- P Huang
- Molecular Research Institute, Palo Alto, CA 94304, USA
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302
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Okuda-Ashitaka E, Tachibana S, Houtani T, Minami T, Masu Y, Nishi M, Takeshima H, Sugimoto T, Ito S. Identification and characterization of an endogenous ligand for opioid receptor homologue ROR-C: its involvement in allodynic response to innocuous stimulus. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 43:96-104. [PMID: 9037523 DOI: 10.1016/s0169-328x(96)00165-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We reported here purification and characterization of a novel heptadecapeptide in bovine brain as an endogenous ligand for ROR-C, an opioid receptor homologue cloned from rat cerebrum. The amino acid sequence of the peptide that we purified is identical to those recently identified as nociceptin in rat brain and orphanin FQ in porcine brain. The peptide inhibited the forskolin-induced cyclic AMP accumulation in ROR-C expressing Chinese hamster ovary cells. Studies on inhibitory activity of cyclic AMP accumulation and Northern blot analysis showed that the peptide and its precursor mRNA are present in a number of brain regions, less abundant in the spina cord, and negligible in the cerebellum. In situ hybridization analysis revealed that hybridization-positive neurons were distributed in the superficial layer (lamina I) of the dorsal horn and were also interspersed between the tract of Lissauer in the spinal cord. Intrathecal administration of the peptide into conscious mice induced allodynia, a pain response to innocuous tactile stimuli, in a beli-shaped manner. These results demonstrate that the peptide exists in the brain and spinal cord and plays an important role in pain transmission.
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Affiliation(s)
- E Okuda-Ashitaka
- Department of Medical Chemistry, Kansai Medical University, Moriguchi, Japan
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303
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Obermeier H, Wehmeyer A, Schulz R. Expression of mu-, delta- and kappa-opioid receptors in baculovirus-infected insect cells. Eur J Pharmacol 1996; 318:161-6. [PMID: 9007528 DOI: 10.1016/s0014-2999(96)00743-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The mu-, delta- and kappa-opioid receptors have been expressed in Sf9 and 'High Five' insect cells using the baculovirus expression system. In both cell lines highest receptor levels (pmol/mg membrane protein) were observed 48 h after infection. Concomitant exposure to the narcotic antagonist naloxone (1 microM) enhanced the production of each receptor type. However, "High Five' cells differed from Sf9 cells in a 2-3-fold higher receptor density in the cell membrane and were therefore employed for receptor characterization. In membranes of 'High Five' cells opioid receptor levels ranged from 1.0 +/- 0.2 pmol/mg protein for the kappa-opioid receptor, 1.7 +/- 0.2 pmol/mg for the delta-opioid receptor to 2.1 +/- 0.5 pmol/mg for the mu-opioid receptor. The mu-, delta- and kappa-opioid receptor agonists [D-Ala2,N-methyl-Phe4-Gly-ol5]enkephalin ([3H]DAMGO), [D-Pen2,D-Pen5]enkephalin ([3H]DPDPE) and (5 alpha, 7 alpha, 8 beta)-(+)-N-methyl-N-(7-(1-pyrrolidinyl-1-oxaspiro(4,5)dec-8-yl) benzeneacetamide ([3H]U69,563) bound to the opioid receptors with Kd values of 3.4 +/- 0.3 nM, 4.5 +/- 0.1 nM and 1.2 +/- 0.3 nM, respectively, resembling those reported for opioid receptors expressed in mammalian cells. Testing the functionality of the receptors in 'High Five' cells, we found that high affinity agonist binding was strongly reduced in the presence of GTP gamma S/sodium, indicating their coupling to G proteins. Furthermore, activation of the three receptor types inhibited forskolin-stimulated cAMP formation. The results presented here suggest that the 'High Five' cell/baculovirus system provides a convenient method for high level expression of functionally intact opioid receptors as judged by receptor binding studies, their G-protein coupling and inhibition of adenylyl cyclase.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Animals
- Baculoviridae/genetics
- Benzeneacetamides
- Cell Line
- Cyclic AMP/biosynthesis
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins/pharmacology
- GTP-Binding Proteins/metabolism
- Insecta
- Kinetics
- Protein Binding
- Pyrrolidines/pharmacology
- Receptors, Opioid/agonists
- Receptors, Opioid/biosynthesis
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, kappa/biosynthesis
- Receptors, Opioid, mu/biosynthesis
- Recombinant Proteins/agonists
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/metabolism
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Affiliation(s)
- H Obermeier
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians University Munich, Germany
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304
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Heteromultimerization of G-protein-gated inwardly rectifying K+ channel proteins GIRK1 and GIRK2 and their altered expression in weaver brain. J Neurosci 1996. [PMID: 8929423 DOI: 10.1523/jneurosci.16-22-07137.1996] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The weaver (wv) gene (GIRK2) is a member of the G-protein-gated inwardly rectifying potassium (GIRK) channel family, known effectors in the signal transduction pathway of neurotransmitters such as acetylcholine, dopamine, opioid peptides, and substance P in modulation of neurotransmitter release and neuronal excitability. GIRK2 immunoreactivity is found in but not limited to brain regions known to be affected in wv mice, such as the cerebellar granule cells and dopaminergic neurons in the substantia nigra pars compacta. It is also observed in the ventral tegmental area, hippocampus, cerebral cortex, and thalamus. GIRK2 and GIRK1, a related family member, have overlapping yet distinct distributions in rat and mouse brains. In regions where both channel proteins are expressed, such as the cerebral cortex, hippocampus, and cerebellum, they can be co-immunoprecipitated, indicating that they interact to form heteromeric channels in vivo. In the brain of the wv mouse, GIRK2 expression is decreased dramatically. In regions where GIRK1 and GIRK2 distributions overlap, both GIRK1 and GIRK2 expressions are severely disrupted, probably because of their co-assembly. The expression patterns of these GIRK channel subunits provide a basis for consideration of the machinery for neuronal signaling as well as the differential effects of the wv mutation in various neurons.
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305
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Abstract
Studies on dynorphin involvement in epilepsy are summarised in this review. Electrophysiological, biochemical and pharmacological data support the hypothesis that dynorphin is implicated in specific types of seizures. There is clear evidence that this is true for complex partial (limbic) seizures, i.e. those characteristic of temporal lobe epilepsy, because; (1) dynorphin is highly expressed in various parts of the limbic system, and particularly in the granule cells of the hippocampus; (2) dynorphin appears to be released in the hippocampus (and in other brain areas) during complex partial seizures; (3) released dynorphin inhibits excitatory neurotransmission at multiple synapses in the hippocampus via activation of kappa opioid receptors; (4) kappa opioid receptor agonists are highly effective against limbic seizures. Data on generalised tonic-clonic seizures are less straightforward. Dynorphin release appears to occur after ECS seizures and kappa agonists exert a clear anticonvulsant effect in this model. However, more uncertain biochemical data and lack of efficacy of kappa agonists in other generalised tonic-clonic seizure models argue that the involvement of dynorphin in this seizure type may not be paramount. Finally, an involvement of dynorphin in generalised absence seizures appears unlikely on the basis of available data. This may not be surprising, given the presumed origin of absence seizures in alterations of the thalamo-cortical circuit and the low representation of dynorphin in the thalamus. In conclusion, it may be suggested that dynorphin plays a role as an endogenous anticonvulsant in complex partial seizures and in some cases of tonic-clonic seizures, but most likely not in generalised absence. This pattern of effects may coincide with the antiseizure spectrum of selective kappa agonists.
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Affiliation(s)
- M Simonato
- Institute of Pharmacology and Biotechnology Centre, University of Ferrara, Italy
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306
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Burt AR, Carr IC, Mullaney I, Anderson NG, Milligan G. Agonist activation of p42 and p44 mitogen-activated protein kinases following expression of the mouse delta opioid receptor in Rat-1 fibroblasts: effects of receptor expression levels and comparisons with G-protein activation. Biochem J 1996; 320 ( Pt 1):227-35. [PMID: 8947492 PMCID: PMC1217922 DOI: 10.1042/bj3200227] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Rat-1 fibroblasts were transfected with a cDNA encoding the mouse delta opioid receptor. Two separate clones, D2 (which expressed some 6 pmol of the receptor/mg of membrane protein) and DOE (which expressed some 0.2 pmol/mg of membrane protein), were examined in detail. With membranes from both clones, the opioid agonist [D-Ala2]leucine enkephalin (DADLE) caused stimulation of high-affinity GTPase activity and of the binding of guanosine 5'-[gamma-[35S]thio]triphosphate, and inhibition of forskolin-amplified adenylate cyclase activity. DADLE also induced phosphorylation and activation of both the p42MAPK (42 kDa isoform) and p44MAPK (44 kDa isoform) members of the mitogen-activated protein kinase (MAP kinase) family. All of these effects of DADLE were prevented in both clones by pretreatment of the cells with pertussis toxin. The maximal response that could be produced by DADLE in direct assays of G-protein activation were substantially greater in clone D2 than in clone DOE, but in both clones essentially full phosphorylation of both p42MAPK and p44MAPK could be achieved. EC50 values for DADLE stimulation of GTPase activity and for activation of p44MAPK were substantially lower in clone D2 than in clone DOE. Moreover, in both clones the EC50 value for DADLE stimulation of p44MAPK was substantially lower than that for stimulation of GTPase activity, and the Hill coefficients for agonist activation of p44MAPK (h > 1) displayed marked co-operativity whereas those for G-protein activation did not (h 0.8-1.0). DADLE activation of p44MAPK showed more sustained kinetics in clone D2 than in clone DOE. By contrast, lysophosphatidic acid, acting at an endogenously expressed G-protein-coupled receptor, also activated p44MAPK in both clones in a pertussis toxinsensitive manner, but both the kinetics and the concentration-response curve for activation of p44MAPK by this ligand were similar. As with other systems, maintained cellular levels of a cAMP analogue prevented the effects of both G-protein-coupled receptors on activation of p44MAPK. These results demonstrate for the first time that an opioid receptor, at least when expressed in Rat-1 fibroblasts, is able to initiate activation of the MAP kinase cascade in a G1-dependent manner, and show that only a very small proportion of the cellular G1 population is required to be activated to result in full phosphorylation of the p42MAPK and p44MAPK MAP kinases.
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Affiliation(s)
- A R Burt
- Division of Biochemistry and Molecular Biology, University of Glasgow, Scotland, U.K
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307
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Liao YJ, Jan YN, Jan LY. Heteromultimerization of G-protein-gated inwardly rectifying K+ channel proteins GIRK1 and GIRK2 and their altered expression in weaver brain. J Neurosci 1996; 16:7137-50. [PMID: 8929423 PMCID: PMC6578936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/1996] [Accepted: 08/22/1996] [Indexed: 02/03/2023] Open
Abstract
The weaver (wv) gene (GIRK2) is a member of the G-protein-gated inwardly rectifying potassium (GIRK) channel family, known effectors in the signal transduction pathway of neurotransmitters such as acetylcholine, dopamine, opioid peptides, and substance P in modulation of neurotransmitter release and neuronal excitability. GIRK2 immunoreactivity is found in but not limited to brain regions known to be affected in wv mice, such as the cerebellar granule cells and dopaminergic neurons in the substantia nigra pars compacta. It is also observed in the ventral tegmental area, hippocampus, cerebral cortex, and thalamus. GIRK2 and GIRK1, a related family member, have overlapping yet distinct distributions in rat and mouse brains. In regions where both channel proteins are expressed, such as the cerebral cortex, hippocampus, and cerebellum, they can be co-immunoprecipitated, indicating that they interact to form heteromeric channels in vivo. In the brain of the wv mouse, GIRK2 expression is decreased dramatically. In regions where GIRK1 and GIRK2 distributions overlap, both GIRK1 and GIRK2 expressions are severely disrupted, probably because of their co-assembly. The expression patterns of these GIRK channel subunits provide a basis for consideration of the machinery for neuronal signaling as well as the differential effects of the wv mutation in various neurons.
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Affiliation(s)
- Y J Liao
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco 94143-0724, USA
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308
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Piros ET, Hales TG, Evans CJ. Functional analysis of cloned opioid receptors in transfected cell lines. Neurochem Res 1996; 21:1277-85. [PMID: 8947917 DOI: 10.1007/bf02532368] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Opioids modulate numerous central and peripheral processes including pain perception neuroendocrine secretion and the immune response. The opioid signal is transduced from receptors through G proteins to various different effectors. Heterogeneity exists at all levels of the transduction process. There are numerous endogenous ligands with differing selectivities for at least three distinct opioid receptors (mu, delta, kappa). G proteins activated by opioid receptors are generally of the pertussis toxin-sensitive Gi/Go class, but there are also opioid actions that are thought to involve Gq and cholera toxin-sensitive G proteins. To further complicate the issue, the actions of opioid receptors may be mediated by G-protein alpha subunits and/or beta gamma subunits. Subsequent to G protein activation several effectors are known to orchestrate the opioid signal. For example activation of opioid receptors increases phosphatidyl inositol turnover, activates K+ channels and reduces adenylyl cyclase and Ca2+ channel activities. Each of these effectors shows considerable heterogeneity. In this review we examine the opioid signal transduction mechanism. Several important questions arise: Why do opioid ligands with similar binding affinities have different potencies in functional assays? To which Ca2+ channel subtypes do opioid receptors couple? Do opioid receptors couple to Ca2+ channels through direct G protein interactions? Does the opioid-induced inhibition of vesicular release occur through modulation of multiple effectors? We are attempting to answer these questions by expressing cloned opioid receptors in GH3 cells. Using this well characterized system we can study the entire opioid signal transduction process from ligand-receptor interaction to G protein-effector coupling and subsequent inhibition of vesicular release.
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MESH Headings
- Animals
- Cell Line
- Cyclic AMP/metabolism
- GTP-Binding Proteins/metabolism
- Humans
- Inositol Phosphates/metabolism
- Models, Biological
- Narcotics/pharmacology
- Receptors, Opioid/biosynthesis
- Receptors, Opioid/physiology
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, kappa/biosynthesis
- Receptors, Opioid, kappa/physiology
- Receptors, Opioid, mu/biosynthesis
- Receptors, Opioid, mu/physiology
- Recombinant Proteins/biosynthesis
- Signal Transduction
- Transfection/methods
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Affiliation(s)
- E T Piros
- Department of Psychiatry and Biobehavioral Sciences, University of California, School of Medicine, Los Angeles 90095, USA
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309
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Metzger TG, Paterlini MG, Portoghese PS, Ferguson DM. Application of the message-address concept to the docking of naltrexone and selective naltrexone-derived opioid antagonists into opioid receptor models. Neurochem Res 1996; 21:1287-94. [PMID: 8947918 DOI: 10.1007/bf02532369] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A binding site model for the opioid family of G-protein coupled receptors (GPCRs) is proposed based on the message-address concept of ligand recognition. Using ligand docking studies of the universal opioid antagonist, naltrexone, the structural basis for "message' recognition is explored across all three receptor types, mu, delta, and kappa. The binding mode proposed and basis for selectivity are also rationalized using the naltrexone-derived ligands, naltrindole (NTI) and norbinaltorphimine (nor BNI). These ligands are docked to the receptor according to the common naltrexone core or message. The resulting orientation places key "address' elements in close proximity to amino acid residues critical to selectivity among receptors types. Selectivity is explained by sequence differences in the mu, delta, and kappa receptors at these recognition points. Support for the model is derived from site directed mutagenesis studies and ligand binding data for the opioid receptors and other related GPCRs.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Conserved Sequence
- GTP-Binding Proteins/metabolism
- Models, Molecular
- Models, Structural
- Molecular Conformation
- Molecular Sequence Data
- Naltrexone/analogs & derivatives
- Naltrexone/chemistry
- Naltrexone/metabolism
- Narcotic Antagonists/chemistry
- Narcotic Antagonists/metabolism
- Protein Conformation
- Receptors, Opioid, delta/chemistry
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/chemistry
- Receptors, Opioid, kappa/metabolism
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Affiliation(s)
- T G Metzger
- Department of Medicinal Chemistry and Minnesota Supercomputer Institute, University of Minnesota, Minneapolis 55455, USA
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310
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Chen XH, Liu-Chen LY, Tallarida RJ, Geller EB, de Riel JK, Adler MW. Use of a mu-antisense oligodeoxynucleotide as a mu opioid receptor noncompetitive antagonist in vivo. Neurochem Res 1996; 21:1363-8. [PMID: 8947926 DOI: 10.1007/bf02532377] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We examined whether mu-antisense (AS) oligodeoxynucleotide (oligo) treatment can be used in a manner similar to the mu-selective irreversible antagonist beta-funaltrexamine (beta-FNA) for in vivo pharmacology. Rats were injected intracerebroventricularly (icv) with a mu-AS or a missense (MS) oligo on days 1, 3, 5, 7, and 9 and were tested for the antinociceptive effect of sc injection of morphine on days 2, 4, 6, 8, and 10 in the cold water tail-flick (CWT) test. In another set of experiments, rats were also tested for the antinociceptive action of morphine twenty-four hours after icv injection of beta-FNA. Both beta-FNA and mu-AS produced rightward shifts in the dose-effect curves of morphine. In addition, pretreatment with 2.5 micrograms or more of beta-FNA or the mu-AS oligo for 5-9 days (but not for 1-3 days) reduced the maximal analgesic effect of morphine. The approximate fraction of functional receptor remaining for morphine was determined with the method of Furchgott to be 49.5% following 2.5 micrograms of beta-FNA; that after 5 days of the mu-AS oligo treatment was 50.8%. The results suggest that the mu-AS oligo can be used in the same manner as highly selective, irreversible mu opioid receptor ligands. Thus, properly designed AS oligos against receptors are of particular benefit when irreversible antagonists are not available. AS oligos represent a new class of selective and powerful pharmacological antagonists.
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MESH Headings
- Animals
- Base Sequence
- Cerebral Ventricles/drug effects
- Cerebral Ventricles/physiology
- Injections, Intraventricular
- Injections, Subcutaneous
- Male
- Molecular Sequence Data
- Morphine/administration & dosage
- Morphine/pharmacology
- Naltrexone/administration & dosage
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/pharmacology
- Oligonucleotides, Antisense/administration & dosage
- Oligonucleotides, Antisense/pharmacology
- Pain
- Rats
- Rats, Sprague-Dawley
- Reaction Time/drug effects
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/physiology
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Affiliation(s)
- X H Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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311
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Carpenter KA, Wilkes BC, Weltrowska G, Schiller PW. Role of hydrophobic substituents in the interaction of opioid Tyr-Tic dipeptide analogs with dodecylphosphocholine micelles. Molecular partitioning in model membrane systems. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:756-64. [PMID: 8944763 DOI: 10.1111/j.1432-1033.1996.00756.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The conformational properties of three Tyr-Tic-NH-R dipeptide analogs [where R = (CH2)2-Ph, (CH2)3-Ph or (CH2)2-cHx; Ph = phenyl; cHx = cyclohexyl and Tic = tetrahydroisoquinoline-3-carboxylic acid] have been investigated in purely aqueous solution and in the presence of fully deuterated dodecylphosphocholine micelles. H-Tyr-Tic-NH-(CH2)2-Ph is an opioid delta-agonist, whereas H-Tyr-Tic-NH-(CH2)3-Ph is a fairly potent delta-antagonist. H-Tyr-Tic-NH-(CH2)2-cHx is a less potent delta-antagonist. 1H-NMR spectra revealed that conformers containing cis and trans configurations of the Tyr-Tic peptide bond were present in all compounds in H2O and the H2O/lipid solvent. Analyses of the NMR data for the compounds in H2O indicate that in all three dipeptides the C-terminal substituent is flexible and the Tyr-side-chain adopts a trans orientation in most of the conformations. This promotes a compact Tyr-Tic structure. NOE patterns observed for the compounds in the micelle solution indicate that Tyr has an even greater tendency to assume a trans side chain configuration in the biphasic-solvent system. This feature was more pronounced in the trans conformers than in the cis conformers. Specific lipid-peptide interactions were indicated by NOESY spectra acquired for micelle samples incorporating 20% (by mass) protonated lipid. According to the obtained NOE data, Tyr and Tic form an aromatic cluster which preferentially inserts into the lipid interior of the micelle for the trans conformers of all three dipeptides and for the cis conformer of H-Tyr-Tic-NH-(CH2)2-Ph. For the cis isomers, partitioning of the C-terminal substituents into the lipid phase exhibited more diverse behaviour. The cis conformers of H-Tyr-Tic-NH-(CH2)3-Ph and H-Tyr-Tic-NH-(CH2)2-cHx preferentially anchor to the micelle via their C-terminal substituent, while the corresponding region in H-Tyr-Tic-NH-(CH2)2-Ph remains flexible and immersed in the aqueous phase. The inconsistent mode of peptide-micelle interaction observed for cis conformers of the three compounds studied is explained in terms of differences in their dipeptide-substituent hydrophobicities. The more apolar the substituent, the greater its tendency to preferentially insert into the lipid core of the micelle. Amide-proton temperature coefficients measured for the three peptides revealed differences amongst the cis and trans isomers. The amide proton in the trans conformer of each compound is highly exposed to the aqueous phase in both solvent systems studied, whereas the cis NH proton of each peptide is only partially exposed. These results demonstrate that a subtle structural modification of an active peptide analog can result in dramatic changes of its biological activity and its mode of partitioning at a membrane surface.
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Affiliation(s)
- K A Carpenter
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, Canada
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312
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Scholz J, Steinfath M, Schulz M. Clinical pharmacokinetics of alfentanil, fentanyl and sufentanil. An update. Clin Pharmacokinet 1996; 31:275-92. [PMID: 8896944 DOI: 10.2165/00003088-199631040-00004] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Alfentanil, fentanyl and sufentanil are synthetic opioid analgesics acting at specific opioid receptors. These opioids are widely used as analgesics to supplement general anaesthesia for various surgical procedures or as primary anaesthetic agents in very high doses during cardiac surgery. Fentanyl and sufentanil especially are administered via infusion for long term analgesia and sedation in intensive care patients. Opioid analgesics are mainly administered using the intravenous route. However, other techniques of administration, including epidural, intrathecal, transdermal and intranasal applications, have been demonstrated. Important pharmacokinetic differences between alfentanil, fentanyl and sufentanil have been shown in many reports. Alfentanil has the most rapid analgesic onset and time to peak effect as well as the shortest distribution and elimination half-lives. The volume of distribution and total body clearance of this agent are smaller when compared with those of fentanyl and sufentanil. The pharmacokinetics of the opioid analgesics can be affected by several factors including patient age, plasma protein content, acid-base status and cardiopulmonary bypass, but not significantly by renal insufficiency or compensated hepatic dysfunction. In addition, pharmacokinetic properties can be influenced by changes in hepatic blood flow and administration of drug combinations which compete for the same plasma protein carrier or metabolising pathway. Although comparing specific pharmacokinetic parameters such as half-lives is deeply entrenched in the literature and clinical practice, simply comparing half-lives is not a rational way to select an opioid for specific requirements. Using pharmacokinetic-pharmacodynamic models, computer simulations based on changes in the effect site opioid concentration or context-sensitive half-times seem to be extremely useful for selecting an opioid on a more rational basis.
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Affiliation(s)
- J Scholz
- Department of Anaesthesiology, University of Hamburg, University Hospital Eppendorf, Germany
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313
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Li X, Keith DE, Evans CJ. Mu opioid receptor-like sequences are present throughout vertebrate evolution. J Mol Evol 1996; 43:179-84. [PMID: 8703083 DOI: 10.1007/bf02338825] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
Abstract
The sequence of the mu opioid receptor is highly conserved among human, rat, and mouse. In order to gain insights into the evolution of the mu opioid receptor, polymerase chain reaction (PCR) was used to screen genomic DNA from a number of different species using degenerate oligonucleotides which recognize a highly conserved region. DNA was assayed from representative species of both the protostome and deuterostome branches of the metazoan phylogenetic tree. Mu opioid receptor-like sequences were found in all vertebrate species that were analyzed. These species included bovine, chicken, bullfrog, striped bass, thresher shark, and Pacific hagfish. However, no mu opioid receptor-like sequences were detected from protostomes or from any invertebrates. The PCR results demonstrate that the region of the mu opioid receptor gene between the first intracellular loop and the third transmembrane domain (TM3) has been highly conserved during evolution and that mu opioid receptor-like sequences are present in the earliest stages of vertebrate evolution. Additional opioid receptor-like sequence was obtained from mRNA isolated from Pacific hagfish brain using rapid amplification of cDNA ends (RACE). The sequence of the Pacific hagfish was most homologous with the human mu opioid receptor (72% at the amino acid level between intracellular loop 1 and transmembrane domain 6) although over the same region high homology was also observed with the delta opioid receptor (69%), the kappa receptor (63%), and opioid receptor-like (ORL1) (59%). The hagfish sequence showed low conservation with the mammalian opioid receptors in the first and second extracellular loops but high conservation in the transmembrane and intracellular domains.
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Affiliation(s)
- X Li
- Department of Psychiatry and Biobehavioral Sciences, School of Medicine, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA
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314
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Keith DE, Murray SR, Zaki PA, Chu PC, Lissin DV, Kang L, Evans CJ, von Zastrow M. Morphine activates opioid receptors without causing their rapid internalization. J Biol Chem 1996; 271:19021-4. [PMID: 8702570 DOI: 10.1074/jbc.271.32.19021] [Citation(s) in RCA: 401] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We have examined the endocytic trafficking of epitope-tagged delta and mu opioid receptors expressed in human embryonic kidney (HEK) 293 cells. These receptors are activated by peptide agonists (enkephalins) as well as by the alkaloid agonist drugs etorphine and morphine. Enkephalins and etorphine cause opioid receptors to internalize rapidly (t1/2 approximately 6 min) by a mechanism similar to that utilized by a number of other classes of receptor, as indicated by localization of internalized opioid receptors in transferrin-containing endosomes and inhibition of opioid receptor internalization by hypertonic media. Remarkably, morphine does not stimulate the rapid internalization of either delta or mu opioid receptors, even at high concentrations that strongly inhibit adenylyl cyclase. These data indicate that agonist ligands, which have similar effects on receptor-mediated signaling, can have dramatically different effects on the intracellular trafficking of a G protein-coupled receptor.
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Affiliation(s)
- D E Keith
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California 90024, USA
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315
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Cheng PY, Liu-Chen LY, Chen C, Pickel VM. Immunolabeling of Mu opioid receptors in the rat nucleus of the solitary tract: extrasynaptic plasmalemmal localization and association with Leu5-enkephalin. J Comp Neurol 1996; 371:522-36. [PMID: 8841907 DOI: 10.1002/(sici)1096-9861(19960805)371:4<522::aid-cne3>3.0.co;2-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Activation of the mu opioid receptor (MOR) by morphine within the caudal nucleus of the solitary tract (NTS) is known to mediate both cardiorespiratory and gastrointestinal responses. Leu5-enkephalin (LE), a potential endogenous ligand for MOR, is also present within neurons in this region. To determine the cellular sites for the visceral effects of MOR ligands, including LE, we used immunogold-silver and immunoperoxidase methods for light and electron microscopic localization of antisera against MOR (carboxyl terminal domain) and LE in the caudal NTS of rat brain. Light microscopy of coronal sections through the NTS at the level of the area postrema showed MOR-like immunoreactivity (MOR-LI) and LE labeling in punctate processes located within the subpostremal, dorsomedial and medial subnuclei. Electron microscopy of sections through the medial NTS at this level showed gold-silver particles identifying MOR-LI prominently distributed to the cytoplasmic side of the plasma membranes of axons and terminals. MOR labeled terminals formed mostly symmetric (inhibitory-type) synapses but sometimes showed multiple asymmetric junctions, characteristic of excitatory visceral afferents. MOR-LI was also present along extrasynaptic plasma membranes of dendrites receiving afferent input from unlabeled and LE-labeled terminals. We conclude that MOR ligands, possibly including LE, can act at extrasynaptic MORs on the plasma membranes of axons and dendrites in the caudal NTS to modulate the presynaptic release and postsynaptic responses of neurons. These are likely to include local inhibitory neurons and both gastric and cardiorespiratory afferents known to terminate in the subnuclei with the most intense MOR-LI.
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Affiliation(s)
- P Y Cheng
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021, USA.
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316
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Drake CT, Patterson TA, Simmons ML, Chavkin C, Milner TA. Kappa opioid receptor-like immunoreactivity in guinea pig brain: ultrastructural localization in presynaptic terminals in hippocampal formation. J Comp Neurol 1996; 370:377-95. [PMID: 8799863 DOI: 10.1002/(sici)1096-9861(19960701)370:3<377::aid-cne8>3.0.co;2-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Physiological and pharmacological studies have suggested that kappa opioid receptors (KORs) may be located presynaptically in the guinea pig hippocampal formation. In the present study, KOR-like immunoreactivity (-LI) was examined by using a rabbit antibody raised against a synthetic peptide from the carboxyl terminus of a cloned rat kappa receptor (KT). The specificity of affinity-purified KT antibody was confirmed by Western blotting, enzyme-linked immunosorbent assay, immunolabeling of KORs expressed in Xenopus oocytes, and immunocytochemical preadsorption controls. Specificity also was demonstrated by the light microscopic distribution of KT-LI in sections through the forebrain and the pons, which was largely consistent with the distribution of KORs previously reported, and resembled that of immunoreactivity for dynorphin B, an endogenous ligand for KORs. Detailed analysis of the hippocampal formation revealed that KT-LI was located predominantly in thin processes in the granule cell and inner molecular layers of the dentate gyrus. A few KT-labeled processes were also present in stratum lacunosum-moleculare of the CA1 region and all layers of the CA3 region of the hippocampus. By electron microscopy, KT-LI was restricted to unmyelinated axons and axon terminals, and was associated with plasma membranes, large dense-core vesicles, and cytoplasmic surfaces of small vesicles. In the dentate gyrus, immunolabeled terminals formed asymmetric synapses with granule cell perikarya and large unlabeled dendrites. In the CA3 region of hippocampus, KT-LI was present in small unmyelinated axons. The results of this study 1) demonstrate the specificity of the KT antibody, 2) show that the distribution of KT labeling corresponds well with previous KOR and dynorphin localization in many regions, and 3) provide ultrastructural evidence that KORs are located presynaptically in the guinea pig hippocampal formation.
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Affiliation(s)
- C T Drake
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021, USA
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317
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Claude PA, Wotta DR, Zhang XH, Prather PL, McGinn TM, Erickson LJ, Loh HH, Law PY. Mutation of a conserved serine in TM4 of opioid receptors confers full agonistic properties to classical antagonists. Proc Natl Acad Sci U S A 1996; 93:5715-9. [PMID: 8650158 PMCID: PMC39126 DOI: 10.1073/pnas.93.12.5715] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The involvement of a conserved serine (Ser196 at the mu-, Ser177 at the delta-, and Ser187 at the kappa-opioid receptor) in receptor activation is demonstrated by site-directed mutagenesis. It was initially observed during our functional screening of a mu/delta-opioid chimeric receptor, mu delta2, that classical opioid antagonists such as naloxone, naltrexone, naltriben, and H-Tyr-Tic[psi,CH2NH]Phe-Phe-OH (TIPPpsi; Tic = 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) could inhibit forskolin-stimulated adenylyl cyclase activity in CHO cells stably expressing the chimeric receptor. Antagonists also activated the G protein-coupled inward rectifying potassium channel (GIRK1) in Xenopus oocytes coexpressing the mu delta2 opioid receptor and the GIRK1 channel. By sequence analysis and back mutation, it was determined that the observed antagonist activity was due to the mutation of a conserved serine to leucine in the fourth transmembrane domain (S196L). The importance of this serine was further demonstrated by analogous mutations created in the mu-opioid receptor (MORS196L) and delta-opioid receptor (DORS177L), in which classical opioid antagonists could inhibit forskolin-stimulated adenylyl cyclase activity in CHO cells stably expressing either MORS196L or DORS177L. Again, antagonists could activate the GIRK1 channel coexpressed with either MORS196L or DORS177L in Xenopus oocytes. These data taken together suggest a crucial role for this serine residue in opioid receptor activation.
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Affiliation(s)
- P A Claude
- Department of Pharmacology, Medical School, University of Minnesota, Minneapolis, 55455, USA
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318
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Brandt W, Drosihn S, Haurand M, Holzgrabe U, Nachtsheim C. Search for the pharmacophore in kappa-agonistic diazabicyclo[3.3.1]nonan-9-one-1,5-diesters and arylacetamides. Arch Pharm (Weinheim) 1996; 329:311-23. [PMID: 8767114 DOI: 10.1002/ardp.19963290607] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several heterocyclic bicyclo[3.3.1]nonan-9-ones were found to have a high affinity to kappa opioid receptors, 3,7-Diazabicyclononanones with 2,4-dipyridyl side chains were the most potent agonists whereas the corresponding 3-oxa-7-azabicyclo[3.3.1]nonan-9-one and compounds with phenyl substituents in 2 and 4 position are almost inactive. The purpose of this study was to unravel the active conformation of the bicyclononanones using well-known kappa-selective agonists such as ketocyclazocine, arylacetamides, several isoquinolines, CI-977, and four stereoisomers of EMD-61753 for comparison. In order to determine the geometry of the diazabicycles in solution pH-dependent NMR measurements of the bicycles were recorded and the results were related to the geometries of the aforementioned kappa agonists obtained from semiempirical PM3 calculations. A chair-boat conformation and a protonation at the N7 nitrogen atom of the diazabicyclononanones were found to be the pharmacophoric conformation. Comparison of the spatial arrangements, electrostatic, hydrophobic, and hydrogen bonding potentials of all kappa-selective agonists led to a model of structure-activity relationships of ligands of the kappa receptor. The arrangement of the pharmacophoric elements is characterized by an almost parallel orientation of a carbonyl and a protonated NH function in conjunction with at least one aromatic ring. Ketocyclazocine is only able to adopt this parallel orientation when the nitrogen is inverted relative to the X-ray structure. Furthermore, two binding sites for the aromatic rings are discussed. The pharmacological results of all considered bicyclononanone derivatives as well as of the four enantiomers of EMD-61753 can be understood and consistently explained in this way.
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Affiliation(s)
- W Brandt
- Pharmazeutisches Institut, Universität Bonn, Germany
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319
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Abstract
The stereochemical requirements for omega-opioid receptor binding of a series of linear peptide antagonists with a novel conformationally restricted Phe analogue (Tic) as a second residue were examined by using a variety of computational chemistry methods. The omega-opioid receptor analogues with significant affinity, Tyr-Tic-NH2(TI-NH2), Tyr-Tic-Phe-OH(TIP), Tyr-Tic-Phe-NH2(TIP-NH2), Tyr-Tic-Phe-Phe-OH(TIPP), Tyr-Tic-Phe-Phe-NH2)(TIPP-NH2), and the low affinity omega-opioid peptides Tyr-Pro-Phe-Pro-NH2(morphiceptin) and Tyr-Phe-Phe-Phe-NH2 (TPPP-NH2), were included in this study. The conformational profiles of these peptides were obtained by consecutive cycles of high and low temperature molecular dynamic stimulations, coupled to molecular mechanical energy minimization carried out until no new conformational minima were obtained. Comparing the results for TPPP-NH2 and TIPP-NH2, the presence of the conformationally restricted Tic residue did not greatly reduce the number of unique low energy conformations, but did allow low energy conformers involving cis bonds between the first two residues. The conformational libraries of these peptides were examined for their ability to satisfy the three key ligand components for receptor recognition already identified by previous studies of high affinity cyclic (Tyr1-D-Pen2-Gly3-Phe4-D-Pen5) enkephalin (DPDPE) type agonists: a protonated amine group, an aromatic ring, and a lipophilic moiety in a specific geometric arrangement. Two types of conformations common to the five high omega-opioid affinity L-Tic analogues were found that satisfied these requirements, one with a cis and the other with a trans peptide bond between the Tyr1 and Tic2 residues. Moreover, both the Tic2 and Phe3 residues could mimic the hydrophobic interactions with the receptor of the Phe4 moiety in the cyclic DPDPE type agonists, consistent with the appreciable affinity of both di- and tripeptides. The low omega-opioid receptor affinity of morphiceptin can be understood as the result of conformational preferences that prevent the fulfillment of this pharmacophore for recognition.
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Affiliation(s)
- T M Chao
- Molecular Research Institute, Palo Alto, California 94304, USA
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320
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Bolognesi ML, Ojala WH, Gleason WB, Griffin JF, Farouz-Grant F, Larson DL, Takemori AE, Portoghese PS. Opioid antagonist activity of naltrexone-derived bivalent ligands: importance of a properly oriented molecular scaffold to guide "address" recognition at kappa opioid receptors. J Med Chem 1996; 39:1816-22. [PMID: 8627605 DOI: 10.1021/jm950807f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The presence of a molecular scaffold to orient a basic group is important for potent and selective kappa opioid antagonist selectivity. An attempt to determine how the geometry of the scaffold affects this selectivity has led to the synthesis of a bivalent ligand (5) whose linker constrains the N17' basic nitrogen (the "address") to a position that is 6.5 A from N17' in the kappa antagonist norBNI (1) when these molecules are superimposed. The fact that compound 5 was found to be a highly selective and potent mu-selective antagonist supports the idea that the position of N17' in 5 precludes effective ion pairing with the nonconserved residue Glu297 on outer loop 3 of the kappa opioid receptor. The high mu receptor binding affinity and in vitro pharmacological selectivity of 5 coupled with its presumed low central nervous system bioavailability suggest that it may be a useful antagonist for the investigation of peripheral mu opioid receptors.
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Affiliation(s)
- M L Bolognesi
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis 55455, USA
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321
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Chang AC, Chao CC, Takemori AE, Gekker G, Hu S, Peterson PK, Portoghese PS. Arylacetamide-derived fluorescent probes: synthesis, biological evaluation, and direct fluorescent labeling of kappa opioid receptors in mouse microglial cells. J Med Chem 1996; 39:1729-35. [PMID: 8648612 DOI: 10.1021/jm950813b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fluorescein isothiocyanate isomer I (FITC-I) conjugates of 2-(3,4-dichlorophenyl)-N-methyl-N-[1-(3- or 4-aminophenyl)-2-(1-pyrrolidinyl)ethyl]acetamide (10 and 14) were prepared either without or with an intervening mono-, di-, or tetraglycyl linker. The 3-substituted fluorescent probes (2-5) were found to retain potent agonist activity in smooth muscle preparations as well as high kappa receptor affinity and selectivity in receptor binding assays. The 4-substituted series (6-9) were substantially less potent than the corresponding 3-substituted compounds. Flow cytometric analysis demonstrated high levels of direct kappa-specific staining of mouse microglial cells by the fluorescent probe 5 containing a tetraglycyl linker, as indicated by a 41% decrease in percent cells positively labeled and a 61% decrease in mean fluorescence intensity in the presence of the kappa-selective antagonist, norbinaltorphimine (norBNI). In similar studies, the probe 2 without a linker exhibited only nonspecific binding. This is the first report of direct, selective staining of kappa opioid receptors by a fluorescent nonpeptide opioid ligand. The results of the present study illustrate the importance of introducing hydrophilic linkers to reduce nonspecific binding of fluorescent probes for opioid receptors.
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Affiliation(s)
- A C Chang
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, 55455, USA
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322
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Mullaney I, Carr IC, Milligan G. Analysis of inverse agonism at the delta opioid receptor after expression in Rat 1 fibroblasts. Biochem J 1996; 315 ( Pt 1):227-34. [PMID: 8670111 PMCID: PMC1217175 DOI: 10.1042/bj3150227] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A cDNA encoding the mouse delta opioid receptor was expressed stably in a Rat 1 fibroblast cell line. Expression of this receptor was demonstrated both in ligand binding studies and by reverse transcriptase-PCR. In membranes of clone D2 cells the opioid peptide [D-Ala(2)]-leucine enkephalin (DADLE) produced a robust, concentration-dependent, stimulation of basal high-affinity GTPase activity; the prototypic opioid antagonist naloxone and the highly selective and potent delta opioid ligands H-Tyr-Tic-Phe-Phe-OH (TIPP) and H-Tyr-Tic[Ch2-NH]Phe-Phe-OH (TIPP[psi]) had little effect but N,N-diallyl-Tyr-Aib-Aib-Phe-Leu (ICI174864) caused a marked dose-dependent inhibition of this activity (Tic, 1,2,3,4-tetrahydroisoquinolin-2-yl-carbonyl]; Aib, alpha-aminobutyric acid). This effect of ICI174864 was reversed by TIPP[psi] and attenuated after treatment of the cells with pertussis toxin. No stimulation by DADLE or inhibition by ICI174864 was observed in Rat 1 fibroblasts that did not express the delta opioid receptor. Basal binding of [(35)S]guanosine 5'-O-(3-thio-triphosphate) to membranes of clone D2 cells was also stimulated by DADLE and inhibited by ICI174864; both of these effects were reversed by co-incubation with TIPP[psi]. When cholera toxin-catalysed [(32)P]ADP-ribosylation was performed on membranes of clone D2 cells in the absence of guanine nucleotides, a 40 kDa G1-family polypeptide was labelled in addition to both the long and short isoforms of Gsalpha. Labelling of the 40 kDa polypeptide was enhanced by addition of DADLE and fully attenuated by addition of ICI174864. In contrast, labelling of the isoforms of Gsalpha was unaffected by either opioid ligand. Again, both the positive effect of DADLE and the inhibitory effect of ICI174864 were prevented by co-incubation with TIPP[psi] which, in isolation, had little effect on cholera toxin-catalysed [(32)P]ADP-ribosylation of either Gs or Gi. These data demonstrate that the delta opioid receptor displays a spontaneous activity when expressed in this genetic background. Attenuation of this activity is produced by ICI174864, which by acting as an 'inverse agonist' in this system, functionally uncouples the expressed receptor from the cellular G-protein population. The complete attenuation of agonist-independent cholera toxin-catalysed [(32)P]ADP-ribosylation of Gi demonstrated that ICI174864 acts as an inverse agonist with high intrinsic activity at this receptor.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Line
- DNA, Complementary/genetics
- Enkephalin, Leucine/analogs & derivatives
- Enkephalin, Leucine/pharmacology
- Enkephalin, Leucine-2-Alanine/pharmacology
- Fibroblasts/physiology
- Fibroblasts/ultrastructure
- GTP Phosphohydrolases/metabolism
- GTP-Binding Proteins/physiology
- Mice
- Molecular Sequence Data
- Narcotic Antagonists/pharmacology
- Pertussis Toxin
- Rats
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/physiology
- Sensitivity and Specificity
- Transfection
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- I Mullaney
- Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, U.K
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323
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Reisine T, Law SF, Blake A, Tallent M. Molecular mechanisms of opiate receptor coupling to G proteins and effector systems. Ann N Y Acad Sci 1996; 780:168-75. [PMID: 8602730 DOI: 10.1111/j.1749-6632.1996.tb15121.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- T Reisine
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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324
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Abstract
To help characterize kappa3 receptors and establish their relationship to traditional mu and delta receptors, we have generated a kappa3-selective monoclonal antibody. Monoclonal antibodies were raised against BE(2)-C cells, a human neuroblastoma cell line containing mu, kappa3, and delta opioid receptors. Of the 5,000 hybridoma cell lines screened, approximately 2,000 hybridomas tested positive against BE(2)-C membranes by ELISA, but only 98 of these were negative against a different neuroblastoma cell line lacking opioid receptors. Supernatants from one hybridoma, 8D8, inhibited up to 90% of 3H-NalBzoH (kappa3) binding without affecting 3H-DAMGO (mu) or 3H-naltrindole (delta) binding in BE(2)-C membranes. The selectivity of the antibody was further demonstrated by its blockade of the inhibition of cAMP accumulation in BE(2)-C cells by the kappa3 agonist NalBzoH but not the mu agonist morphine. Monoclonal antibody 8D8 (mAb8D8) also recognizes kappa3 receptors from mouse, rat, and calf brain. Administered intracerebroventricularly, mAb8D8 blocked kappa3 but not morphine (mu) analgesia in vivo. On Western blots, mAb8D8 recognized a protein with a molecular mass of approximately 70 kilodaltons in BE(2)-C. These studies demonstrate the selectivity of mAb8D8 for kappa3 receptors and provide additional support for the existence of this unique opioid receptor subtype.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Animals
- Antibodies, Monoclonal
- Binding, Competitive/drug effects
- Blotting, Western
- Brain Neoplasms/immunology
- Cyclic AMP/metabolism
- Enzyme-Linked Immunosorbent Assay
- Male
- Mice
- Mice, Inbred Strains
- Neuroblastoma/immunology
- Opioid Peptides/metabolism
- Pain Measurement/drug effects
- Rats
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, kappa/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- A I Brooks
- The Cotzias Laboratory of Neuro-Oncology, Memorial Sloan-Kettering Cancer Center, New York 10021, USA
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325
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Cappelli A, Anzini M, Vomero S, Menziani MC, De Benedetti PG, Sbacchi M, Clarke GD, Mennuni L. Synthesis, biological evaluation, and quantitative receptor docking simulations of 2-[(acylamino)ethyl]-1,4-benzodiazepines as novel tifluadom-like ligands with high affinity and selectivity for kappa-opioid receptors. J Med Chem 1996; 39:860-72. [PMID: 8632410 DOI: 10.1021/jm950423p] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The synthesis and biological evaluation of a series of 2-substituted 5-phenyl-1,4-benzodiazepines, structurally related to tifluadom (5), the only benzodiazepine that acts simultaneously as a kappa-opioid agonist and a cholecystokinin-A (CCK-A) antagonist, are reported. The radioligand binding models used in these studies were [(125)I](BH)-CCK-8 in rat pancreas (CCK-A), [(3)H]-(MENLE(28,31))-cck-8 in guinea pig cerebral cortex (CCK-B), and [(3)H]U-69593 (kappa(1)), [(3)H]DAMGO (mu), and [(3)H]DADLE (delta) in guinea pig brain. All the title compounds were devoid of significant affinity for both CCK-A and CCK-B receptors, while some of them bound with nanomolar affinity and high selectivity for kappa-opioid receptors. In particular, the 2-thienyl derivative 7A(X = H) with a K(i) = 0.50 nM represents a clear improvement with respect to tifluadom, showing a comparable potency but higher selectivity. The application of computational simulations and linear regression analysis techniques to the complexes between guinea pig kappa (kappa(1))-receptor and the title compounds allowed the identification of the structural determinants for recognition and quantitative elucidation of the structure-affinity relationships in this class of receptors.
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MESH Headings
- Amino Acid Sequence
- Analgesics/metabolism
- Animals
- Benzodiazepines/chemical synthesis
- Benzodiazepines/chemistry
- Benzodiazepines/metabolism
- Binding, Competitive
- Brain/metabolism
- Cerebral Cortex/metabolism
- Computer Graphics
- Conserved Sequence
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
- Enkephalin, Leucine-2-Alanine/metabolism
- Enkephalins/metabolism
- Guinea Pigs
- Humans
- Ligands
- Mice
- Models, Molecular
- Molecular Sequence Data
- Molecular Structure
- Pancreas/metabolism
- Protein Conformation
- Radioligand Assay
- Rats
- Receptors, Cholecystokinin/chemistry
- Receptors, Cholecystokinin/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Sequence Homology, Amino Acid
- Sincalide/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- A Cappelli
- Dipartimento Farmaco Chimico Tecnologico, Universitá di Siena, Italy
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326
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Lazarus LH, Bryant SD, Salvadori S, Attila M, Sargent Jones L. Opioid infidelity: novel opioid peptides with dual high affinity for delta- and mu-receptors. Trends Neurosci 1996; 19:31-5. [PMID: 8787139 DOI: 10.1016/0166-2236(96)81864-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Deltorphins represent the paragon of delta-opioid-receptor ligands of natural origin, since they exceed the affinity and selectivity of the endogenous enkephalins by orders of magnitude. A series of opioid peptides have been developed in which the change in a single amino acid causes an extraordinary increase in mu-receptor binding while maintaining high affinity for the delta-receptor. The peptides appear to have a similar extended conformation in solution with a type-I beta-turn in the N-terminus region, suggesting that tertiary architecture plays a pivotal role in enabling the peptide to bind indiscriminately to mu- and delta-receptors. These dual-affinity peptide ligands can serve to mask delta- and mu-receptors while mapping kappa-receptors in the nervous system, to provide an understanding of the differences and similarities in the structure of the binding domains of delta- and mu-receptors, and might lead to a comprehensive new regime for the clinical management of acute and chronic pain.
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Affiliation(s)
- L H Lazarus
- Peptide Neurochemistry, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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327
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Simmons ML, Chavkin C. Endogenous opioid regulation of hippocampal function. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1996; 39:145-96. [PMID: 8894847 DOI: 10.1016/s0074-7742(08)60666-2] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Endogenous opioid peptides modulate neural transmission in the hippocampus. Procnkephalin-derived peptides have been demonstrated to act at mu and delta opioid receptors to inhibit GABA release from inhibitory interneurons, resulting in increased excitability of hippocampal pyramidal cells and dentate gyrus granule cells. Prodynorphin-derived peptides primarily act at presynaptic kappa opioid receptors to inhibit excitatory amino acid release from perforant path and mossy fiber terminals. Opioid receptors reduce membrane excitability by modulating ion conductances, and in this way they may decrease voltage-dependent calcium influx and transmitter release. Synaptic plasticity in the hippocampus also is modulated by endogenous opioids. Enkephalins facilitate long-term potentiation, whereas dynorphins inhibit the induction of this type of neuroplasticity. Further, opioids may play important roles in hippocampal epilepsy. Recurrent seizures induce changes in the expression of opioid peptides and receptors. Also, enkephalins have proconvulsant effects in the epileptic hippocampus, whereas dynorphins may function as endogenous anticonvulsants.
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Affiliation(s)
- M L Simmons
- Department of Pharmacology, University of Washington, Seattle 98195, USA
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328
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Opioids and the Control of Pain. Neurotherapeutics 1996. [DOI: 10.1007/978-1-59259-466-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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329
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Leshner AI. Toward the year 2000. Subst Use Misuse 1996; 31:207-13. [PMID: 8834008 DOI: 10.3109/10826089609045808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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330
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Wang WW, Shahrestanifar M, Jin J, Howells RD. Studies on mu and delta opioid receptor selectivity utilizing chimeric and site-mutagenized receptors. Proc Natl Acad Sci U S A 1995; 92:12436-40. [PMID: 8618916 PMCID: PMC40372 DOI: 10.1073/pnas.92.26.12436] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Opioid receptors are members of the guanine nucleotide binding protein (G protein)-coupled receptor family. Three types of opioid receptors have been cloned and characterized and are referred to as the delta, kappa and mu types. Analysis of receptor chimeras and site-directed mutant receptors has provided a great deal of information about functionally important amino acid side chains that constitute the ligand-binding domains and G-protein-coupling domains of G-protein-coupled receptors. We have constructed delta/mu opioid receptor chimeras that were express in human embryonic kidney 293 cells in order to define receptor domains that are responsible for receptor type selectivity. All chimeric receptors and wild-type delta and mu opioid receptors displayed high-affinity binding of etorphine (an agonist), naloxone (an antagonist), and bremazocine (a mixed agonist/antagonist). In contrast, chimeras that lacked the putative first extracellular loop of the mu receptor did not bind the mu-selective peptide [D-Ala2,MePhe4,Gly5-ol]enkephalin (DAMGO). Chimeras that lacked the putative third extracellular loop of the delta receptor did not bind the delta-selective peptide, [D-Ser2,D-Leu5]enkephalin-Thr (DSLET). Point mutations in the putative third extracellular loop of the wild-type delta receptor that converted vicinal arginine residues to glutamine abolished DSLET binding while not affecting bremazocine, etorphine, and naltrindole binding. We conclude that amino acids in the putative first extracellular loop of the mu receptor are critical for high-affinity DAMGO binding and that arginine residues in the putative third extracellular loop of the delta receptor are important for high-affinity DSLET binding.
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MESH Headings
- Amino Acid Sequence
- Analgesics/metabolism
- Base Sequence
- Benzomorphans/metabolism
- Binding, Competitive
- Cell Line
- Cell Membrane/physiology
- Cell Membrane/ultrastructure
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
- Enkephalin, Leucine/analogs & derivatives
- Enkephalin, Leucine/metabolism
- Enkephalins/metabolism
- Etorphine/metabolism
- GTP-Binding Proteins/metabolism
- Humans
- Kidney
- Kinetics
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Naloxone/metabolism
- Oligodeoxyribonucleotides
- Polymerase Chain Reaction
- Protein Structure, Secondary
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/biosynthesis
- Receptors, Opioid, mu/metabolism
- Recombinant Fusion Proteins/antagonists & inhibitors
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/metabolism
- Substrate Specificity
- Transfection
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Affiliation(s)
- W W Wang
- Department of Biochemistry and Molecular Biology, New Jersey Medical School, Newark 07103, USA
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331
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Kieffer BL. Recent advances in molecular recognition and signal transduction of active peptides: receptors for opioid peptides. Cell Mol Neurobiol 1995; 15:615-35. [PMID: 8719033 DOI: 10.1007/bf02071128] [Citation(s) in RCA: 294] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
1. Opioid peptides are a family of structurally related neuromodulators which play a major role in the control of nociceptive pathways. These peptides act through membrane receptors of the nervous system, defined as mu, delta and kappa and endowed with overlapping but distinct pharmacological, anatomical and functional properties. 2. Recent cloning of an opioid receptor gene family has opened the way to the use of recombinant DNA technology at the receptor level. 3. This review focuses on the molecular cloning and functional characterization of opioid receptors and provides first insights into molecular aspects of opioid peptide recognition and signal transduction mechanisms, using the cloned receptors as investigation tools.
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MESH Headings
- Amino Acid Sequence
- Animals
- Brain/physiology
- Cloning, Molecular
- GTP-Binding Proteins/physiology
- Humans
- Mice
- Molecular Sequence Data
- Multigene Family
- Receptors, Opioid/chemistry
- Receptors, Opioid/genetics
- Receptors, Opioid/physiology
- Receptors, Opioid, delta/chemistry
- Receptors, Opioid, kappa/chemistry
- Receptors, Opioid, mu/chemistry
- Sequence Homology, Amino Acid
- Signal Transduction
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Affiliation(s)
- B L Kieffer
- Ecole Supérieure de Biotechnologie de Strabourg, Illkirch France
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332
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Reinscheid RK, Nothacker HP, Bourson A, Ardati A, Henningsen RA, Bunzow JR, Grandy DK, Langen H, Monsma FJ, Civelli O. Orphanin FQ: a neuropeptide that activates an opioidlike G protein-coupled receptor. Science 1995; 270:792-4. [PMID: 7481766 DOI: 10.1126/science.270.5237.792] [Citation(s) in RCA: 1472] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A heptadecapeptide was identified and purified from porcine brain tissue as a ligand for an orphan heterotrimeric GTP-binding protein (G protein)-coupled receptor (LC132) that is similar in sequence to opioid receptors. This peptide, orphanin FQ, has a primary structure reminiscent of that of opioid peptides. Nanomolar concentrations of orphanin FQ inhibited forskolin-stimulated adenylyl cyclase activity in cells transfected with LC132. This inhibitory activity was not affected by the addition of opioid ligands, nor did the peptide activate opioid receptors. Orphanin FQ bound to its receptor in a saturable manner and with high affinity. When injected intracerebroventricularly into mice, orphanin FQ caused a decrease in locomotor activity but did not induce analgesia in the hot-plate test. However, the peptide produced hyperalgesia in the tail-flick assay. Thus, orphanin FQ may act as a transmitter in the brain by modulating nociceptive and locomotor behavior.
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Affiliation(s)
- R K Reinscheid
- Pharma Division, Hoffmann-La Roche AG, Basel, Switzerland
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333
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Gorodinsky A, Barg J, Belcheva MM, Levy R, McHale RJ, Vogel Z, Coscia CJ. Dynorphins modulate DNA synthesis in fetal brain cell aggregates. J Neurochem 1995; 65:1481-6. [PMID: 7561841 PMCID: PMC2581519 DOI: 10.1046/j.1471-4159.1995.65041481.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previously, opioid peptide analogues, beta-endorphin, and synthetic opiates were found to inhibit DNA synthesis in 7-day fetal rat brain cell aggregates via kappa- and mu-opioid receptors. Here dynorphins and other endogenous opioid peptides were investigated for their effect on DNA synthesis in rat and guinea pig brain cell aggregates. At 1 microM, all dynorphins tested and beta-endorphin inhibited [3H]thymidine incorporation into DNA by 20-38% in 7-day rat brain cell aggregates. The putative epsilon-antagonist beta-endorphin (1-27) did not prevent the effect of beta-endorphin, suggesting that the epsilon-receptor is not involved in opioid inhibition of DNA synthesis. The kappa-selective antagonist norbinaltorphimine blocked dynorphin A or B inhibition of DNA synthesis, implicating a kappa-opioid receptor. In dose-dependency studies, dynorphin B was three orders of magnitude more potent than dynorphin A in the attenuation of thymidine incorporation, indicative of the mediation of its action by a discrete kappa-receptor subtype. The IC50 value of 0.1 nM estimated for dynorphin B is in the physiological range for dynorphins in developing brain. In guinea pig brain cell aggregates, the kappa-receptor agonists U50488, U69593, and dynorphin B reduced thymidine incorporation by 40%. When 21-day aggregates were treated with dynorphins, a 33-86% enhancement of thymidine incorporation was observed. Because both 7- and 21-day aggregates correspond to stages in development when glial cell proliferation is prevalent and glia preferentially express kappa-receptors in rat brain, these findings support the hypothesis that dynorphins modulate glial DNA synthesis during brain ontogeny.
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Affiliation(s)
- A Gorodinsky
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, MO 63104-1079, USA
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334
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Zhang S, Yu L. Identification of dynorphins as endogenous ligands for an opioid receptor-like orphan receptor. J Biol Chem 1995; 270:22772-6. [PMID: 7559404 DOI: 10.1074/jbc.270.39.22772] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
To identify the endogenous ligands for a cloned orphan receptor that shares high degrees of sequence homology with opioid receptors, this orphan receptor was expressed in Xenopus oocytes and in mammalian cell lines CHO-K1 and HEK-293. The coupling of the receptor to a G protein-activated K+ channel was used as a functional assay in oocytes. Endogenous opioid peptide dynorphins were found to activate the K+ channel by stimulating the orphan receptor. This activation was dose-dependent, with EC50 values at 45 and 37 nM for dynorphin A and dynorphin A-(1-13), respectively. The dynorphin effect was antagonized by the non-selective opioid antagonist naloxone but at rather high concentrations in the micromolar range. Naloxone also caused a rightward shift of the dose-response curve for dynorphin A, suggesting a competitive antagonism mechanism. In transiently transfected cells, 5 microM dynorphin A-(1-13) inhibited the forskolin-stimulated cyclic AMP increase by 51 and 35% in CHO-K1 and HEK-293 cells, respectively. Other classes of endogenous opioids, i.e. enkephalins and endorphins, caused very little activation of this receptor. These results suggest that this orphan receptor is a member of the opioid receptor family and that dynorphins are endogenous ligands for this receptor.
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Affiliation(s)
- S Zhang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis 46202, USA
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335
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Simonin F, Gavériaux-Ruff C, Befort K, Matthes H, Lannes B, Micheletti G, Mattéi MG, Charron G, Bloch B, Kieffer B. kappa-Opioid receptor in humans: cDNA and genomic cloning, chromosomal assignment, functional expression, pharmacology, and expression pattern in the central nervous system. Proc Natl Acad Sci U S A 1995; 92:7006-10. [PMID: 7624359 PMCID: PMC41460 DOI: 10.1073/pnas.92.15.7006] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Using the mouse delta-opioid receptor cDNA as a probe, we have isolated genomic clones encoding the human mu- and kappa-opioid receptor genes. Their organization appears similar to that of the human delta receptor gene, with exon-intron boundaries located after putative transmembrane domains 1 and 4. The kappa gene was mapped at position q11-12 in human chromosome 8. A full-length cDNA encoding the human kappa-opioid receptor has been isolated. The cloned receptor expressed in COS cells presents a typical kappa 1 pharmacological profile and is negatively coupled to adenylate cyclase. The expression of kappa-opioid receptor mRNA in human brain, as estimated by reverse transcription-polymerase chain reaction, is consistent with the involvement of kappa-opioid receptors in pain perception, neuroendocrine physiology, affective behavior, and cognition. In situ hybridization studies performed on human fetal spinal cord demonstrate the presence of the transcript specifically in lamina II of the dorsal horn. Some divergences in structural, pharmacological, and anatomical properties are noted between the cloned human and rodent receptors.
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MESH Headings
- Adenylyl Cyclases
- Aged
- Amino Acid Sequence
- Base Sequence
- Central Nervous System/chemistry
- Central Nervous System/physiology
- Chromosome Mapping
- Chromosomes, Human, Pair 8/genetics
- Cloning, Molecular
- DNA, Complementary/genetics
- Exons/genetics
- Genomic Library
- Humans
- In Situ Hybridization
- Ligands
- Middle Aged
- Molecular Sequence Data
- RNA, Messenger/isolation & purification
- Receptors, Opioid, kappa/genetics
- Receptors, Opioid, kappa/isolation & purification
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/isolation & purification
- Receptors, Opioid, mu/metabolism
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction
- Tissue Distribution
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Affiliation(s)
- F Simonin
- Ecole Supérieure de Biotechnologie, Parc d'innovation, Boulevard Sébastien Brandt, Illkirch-Graffenstaden, France
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336
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Abstract
In the past two years, knowledge about the regulation of ion conductances by opioid receptors has expanded in several directions. First, it has now been shown that all three of the major receptor subtypes act on all three of the well recognized effectors, i.e., adenylyl cyclase, calcium channels and potassium channels. Second, the opioid-mediated receptor inhibition of adenylyl cyclase has been linked to the modulation of ion channel activity /20/. Third, opioids have also been found to increase the activity of adenylyl cyclase in some preparations. Fourth, opioid receptors can mediate a rise in internal free-calcium concentration /21/. These observations suggest that the regulation of cell excitability by opioids is dependent on the cell under study and that the generalization between receptor subtype and specificity of action is no longer valid. The additional second messenger pathways affected by opioids suggest that the adaptive changes resulting from chronic opioid treatment are more complex than previously thought. This review evaluates these relatively new observations and suggests how these results may change the interpretations from previous work on opioid actions.
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Affiliation(s)
- T J Grudt
- Vollum Institute, Oregon Health Sciences University, Portland 97201, USA
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337
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Xue JC, Chen C, Zhu J, Kunapuli SP, Kim de Riel J, Yu L, Liu-Chen LY. The Third Extracellular Loop of the μ Opioid Receptor Is Important for Agonist Selectivity. J Biol Chem 1995. [DOI: 10.1016/s0021-9258(18)92233-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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338
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Meng F, Hoversten MT, Thompson RC, Taylor L, Watson SJ, Akil H. A chimeric study of the molecular basis of affinity and selectivity of the kappa and the delta opioid receptors. Potential role of extracellular domains. J Biol Chem 1995; 270:12730-6. [PMID: 7759527 DOI: 10.1074/jbc.270.21.12730] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Within the large family of G-protein-coupled receptors, a picture is emerging which contrasts the binding of small ligands and the binding of peptides to the seven-helix configuration of the proteins. Because of its unique richness in both peptide and non-peptide ligands, the opioid receptor family offers several advantages for achieving a better understanding of similarities and differences in ligand/receptor interactions across different classes of agonists and antagonists. Since multiple, naturally occurring, ligands interact with the multiple receptors with varying degrees of selectivity, this family is also an excellent model for examining the structural basis of selectivity. Thus, the molecular basis of binding affinity and selectivity of the kappa and the delta opioid receptors was investigated by the construction of four kappa/delta chimeric receptors. The pharmacological profiles of these chimeras as well as those of the wild type kappa and delta receptors were determined by their binding with several different categories of opioid ligands. A linear model was used to deduce the relative contribution of each corresponding pairs of kappa-delta receptor segments to the binding of a given ligand. The results show that the kappa and delta receptors bind the same opioid core differently and achieve their selectivity through different mechanisms. In addition, the interaction of a peptide ligand with a receptor appears to be different from that of a small ligand. Furthermore, these results point to a particularly important role of the second extracellular loop and the top half of transmembrane domain 4 in the binding of prodynorphin products. Together, the results suggest that these peptide receptors can be bound and activated via multiple binding pockets as a function of their own topography and the nature of the interacting ligand.
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Affiliation(s)
- F Meng
- Mental Health Research Institute, University of Michigan, Ann Arbor 48109, USA
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339
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Arvidsson U, Riedl M, Chakrabarti S, Vulchanova L, Lee JH, Nakano AH, Lin X, Loh HH, Law PY, Wessendorf MW. The kappa-opioid receptor is primarily postsynaptic: combined immunohistochemical localization of the receptor and endogenous opioids. Proc Natl Acad Sci U S A 1995; 92:5062-6. [PMID: 7539141 PMCID: PMC41848 DOI: 10.1073/pnas.92.11.5062] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Antisera were raised against a synthetic peptide corresponding to the carboxyl terminus of the kappa-opioid receptor (KOR1). Specificity of the antisera was verified by staining of COS-7 cells transfected with KOR1 and epitope-tagged KOR1 cDNAs, by recognition by the antisera of proteins on Western blots of both transfected cells and brain tissue, by the absence of staining of both brain tissue and transfected cells after preabsorption of the antisera with the cognate peptide, and on the strong correlation between the distribution of KOR1 immunoreactivity and that of earlier ligand binding and in situ hybridization studies. Results indicate that KOR1 in neurons is targeted into both the axonal and somatodendritic compartments, but the majority of immunostaining was seen in the somatodendritic compartment. In sections from rat and guinea pig brain, prominent KOR1 staining was seen in the ventral forebrain, hypothalamus, thalamus, posterior pituitary, and midbrain. While the staining pattern was similar in both species, distinct differences were also observed. The distribution of preprodynorphin and KOR1 immunoreactivity was complementary in many brain regions, suggesting that KOR1 is poised to mediate the physiological actions of dynorphin. However, the distribution of KOR1 and enkephalin immunoreactivity was complementary in some regions as well. These results suggest that the KOR1 protein is primarily, but not exclusively, deployed to postsynaptic membranes where it mediates the effects of products of preprodynorphin and possibly preproenkephalin.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies
- Antibody Specificity
- Blotting, Western
- Brain/cytology
- Brain/metabolism
- Cell Line
- Chlorocebus aethiops
- Dynorphins/analysis
- Epitopes/analysis
- Gene Expression
- Guinea Pigs
- Immunohistochemistry
- Kidney
- Male
- Microscopy, Confocal
- Molecular Sequence Data
- Neuroblastoma
- Neurons/cytology
- Neurons/metabolism
- Organ Specificity
- Peptide Fragments/chemistry
- Peptide Fragments/immunology
- Protein Precursors/analysis
- RNA, Messenger/analysis
- Rabbits/immunology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, kappa/analysis
- Receptors, Opioid, kappa/biosynthesis
- Receptors, Opioid, mu/analysis
- Recombinant Proteins/analysis
- Recombinant Proteins/biosynthesis
- Spinal Cord/cytology
- Spinal Cord/metabolism
- Transfection
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Affiliation(s)
- U Arvidsson
- Department of Cell Biology, University of Minnesota, Minneapolis 55455, USA
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340
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Elde R, Arvidsson U, Riedl M, Vulchanova L, Lee JH, Dado R, Nakano A, Chakrabarti S, Zhang X, Loh HH. Distribution of neuropeptide receptors. New views of peptidergic neurotransmission made possible by antibodies to opioid receptors. Ann N Y Acad Sci 1995; 757:390-404. [PMID: 7611696 DOI: 10.1111/j.1749-6632.1995.tb17497.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The cloning of receptors for neuropeptides made possible studies that identified the neurons that utilize these receptors. In situ hybridization can detect transcripts that encode receptors and thereby identify the cells responsible for their expression, whereas immunocytochemistry enables one to determine the region of the plasma membrane where the receptor is located. We produced antibodies to portions of the predicted amino acid sequences of delta, mu, and kappa opioid receptors and used them in combination with antibodies to a variety of neurotransmitters in multicolor immunofluorescence studies visualized by confocal microscopy. Several findings are notable: First, the cloned delta opioid receptor appears to be distributed primarily in axons, and therefore most likely functions in a presynaptic manner. Second, the cloned mu and kappa opioid receptors are found associated with neuronal plasma membranes of dendrites and cell bodies and therefore most likely function in a postsynaptic manner. However, in certain, discrete populations of neurons, mu and kappa opioid receptors appear to be distributed in axons. Third, enkephalin-containing terminals are often found in close proximity (although not necessarily synaptically linked) to membranes containing either the delta or mu opioid receptors, whereas dynorphin-containing terminals are often found in proximity to kappa opioid receptors. Finally, a substantial mismatch between opioid receptors and their endogenous ligands was observed in some brain regions. However, this mismatch was characterized by complementary zones of receptor and ligand, suggesting underlying principles of organization that underlie long-distance, nonsynaptic neurotransmission.
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Affiliation(s)
- R Elde
- Department of Cell Biology and Neuroanatomy, University of Minnesota Medical School, Minneapolis 55455, USA
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341
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Pasternak GW, Pan YX, Cheng J. Correlating the pharmacology and molecular biology of opioid receptors. Cloning and antisense mapping a kappa 3-related opiate receptor. Ann N Y Acad Sci 1995; 757:332-8. [PMID: 7611690 DOI: 10.1111/j.1749-6632.1995.tb17491.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We cloned a kappa 3-related opioid receptor, and although it is still not clear whether this clone corresponds to the kappa 3 receptor itself or is a related gene product, the extensive antisense mapping and the antibody immunoreactivity strongly associate this clone with the kappa 3 receptor. Our approach also indicates the usefulness of antisense approaches in mapping and identifying orphan receptors. Perhaps it is most effective in identifying partial sequences prior to cloning them in their entirety. It also provides a mechanism of identifying proteins that are not expressed functionally.
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MESH Headings
- Animals
- Cloning, Molecular
- Mice
- Oligonucleotides, Antisense/pharmacology
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, kappa/genetics
- Receptors, Opioid, kappa/immunology
- Receptors, Opioid, mu/drug effects
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Affiliation(s)
- G W Pasternak
- Cotzias Laboratory of Neuro-Oncology Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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342
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Affiliation(s)
- E J Simon
- Department of Psychiatry, New York University Medical Center, New York 10016, USA
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343
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Kim AY, Lee SY, Kim KM. Preparation of δ-opioid receptor-specific antibodies using molecular cloned genes. Arch Pharm Res 1995. [DOI: 10.1007/bf02979143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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344
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Fukuda K, Kato S, Mori K. Location of regions of the opioid receptor involved in selective agonist binding. J Biol Chem 1995; 270:6702-9. [PMID: 7896813 DOI: 10.1074/jbc.270.12.6702] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To elucidate which portions of the opioid receptor molecules are involved in the ligand selectivity, we have expressed chimeric receptors between the rat delta- and mu-opioid receptors from cDNAs and analysed their ligand binding properties. We demonstrate that the major binding determinant for the delta-selective enkephalin-related peptide, [D-Pen2,D-Pen5]enkephalin, resides within the region comprising the transmembrane segments V-VII and the intervening loop regions. On the other hand, the region spanning from the intracellular loop I to the amino-terminal half of the transmembrane segment III is shown to be involved in determining high-affinity binding of the mu-selective enkephalin-related peptides, [D-Ala2, MePhe4,Gly-ol5]enkephalin and [D-Ala2,MePhe4,Met-ol5]enkephalin, whereas the major determinant for binding of the mu-selective alkaloids, morphine and codeine, is demonstrated to exist in the region spanning the transmembrane segments V-VII. These results indicate that distinct regions of the opioid receptor determine the selectivity for the delta- and the mu-selective enkephalin-related peptides and that the binding determinant for the mu-selective alkaloids is distinct from that for the mu-selective enkephalin-related peptides.
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Affiliation(s)
- K Fukuda
- Department of Anesthesia, Kyoto University Hospital, Japan
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345
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Yakovlev AG, Krueger KE, Faden AI. Structure and expression of a rat kappa opioid receptor gene. J Biol Chem 1995; 270:6421-4. [PMID: 7896774 DOI: 10.1074/jbc.270.12.6421] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A gene encoding the rat kappa opioid receptor (KOR) was cloned and characterized. Results of rat genomic library screening and genomic Southern blot analysis show the gene represented at one copy/haploid genome. Three introns are present within the gene; however, polymerase chain reaction using different sets of primers specifying neighboring exons indicates that alternative splicing does not occur. Using reverse transcription-polymerase chain reaction and primer extension techniques, we are able to demonstrate that two species of transcripts are differentially produced from the KOR gene in a tissue-specific manner. The first transcript that we designate as KOR1 is equivalent to the cDNA sequence reported by other groups and is believed to correspond to KOR subtype 1. KOR1 begins with exon 1 just downstream of two TATA boxes, whereas the second transcript, which we refer to as KORx, begins in intron 1 and thereby retains this intronic sequence in the mature mRNA. Within this intronic sequence there are two potential translation initiation codons that are in-frame with the proposed initiation codon of KOR. The potential open reading frame that starts further upstream in KORx may lead to the translation of a variant KOR protein having a novel peptide sequence at its amino terminus.
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Affiliation(s)
- A G Yakovlev
- Department of Neurology, Georgetown University Medical Center, Washington, D.C. 20007
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346
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Steiner H, Gerfen CR. Dynorphin opioid inhibition of cocaine-induced, D1 dopamine receptor-mediated immediate-early gene expression in the striatum. J Comp Neurol 1995; 353:200-12. [PMID: 7745131 DOI: 10.1002/cne.903530204] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neurons in the striatum that project to the substantia nigra contain the opioid peptide dynorphin. Stimulation of D1 dopamine receptors results in increased expression of mRNA encoding dynorphin as well as expression of immediate-early genes such as c-fos in these neurons. Levels of dynorphin vary in different regions of the normal rat striatum, being highest in ventral and medial striatum. In a prior study, we have shown that both regional and temporal patterns of c-fos induction following treatment with the indirect dopamine receptor agonist cocaine are inversely related to those of dynorphin expression. These results suggested that dynorphin is involved in regulating the responsiveness of these neurons to dopamine input. In the present experiments, we examined such a potential role for dynorphin by analyzing the influence of the dynorphin (kappa opioid receptor) agonist spiradoline on immediate-early gene induction by cocaine, and we determined that this immediate-early gene response is mediated by D1 dopamine receptors located in the striatum. As a marker of neuron activation, expression of c-fos and zif 268 immediate-early genes was assessed with quantitative in situ hybridization histochemistry. Results showed that 1) intrastriatal infusion of the D1 dopamine receptor antagonist SCH-23390 (2.5-250 pmol) resulted in a dose-dependent blockade of immediate-early gene induction by cocaine (30 mg/kg); 2 systemic administration of the kappa opioid receptor agonist spiradoline (0.5-10.0 mg/kg) decreased cocaine-induced expression of c-fos and zif 268 mRNAs in striatum in a dose-dependent manner; 3) intrastriatal infusion of spiradoline (1-50 nmol) also suppressed immediate-early gene induction by cocaine, demonstrating that kappa opioid receptors located in the striatum mediate such an effect; and 4) systemic and intrastriatal administration of spiradoline also affected immediate-early gene expression in cortex. These results demonstrate that, in striatum, immediate-early gene induction by cocaine is a D1 dopamine receptor-mediated process that is inhibited by activation of kappa opioid receptors. Therefore, these findings suggest that the striatal dynorphin opioid system acts directly and/or indirectly to inhibit dopamine input to striatonigral neurons through kappa opioid receptor-mediated processes in the striatum.
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Affiliation(s)
- H Steiner
- Section of Neuroanatomy, Laboratory of Systems Neuroscience, National Institute of Mental Health, Bethesda, Maryland 20892-4068, USA
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347
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Lawrence DM, el-Hamouly W, Archer S, Leary JF, Bidlack JM. Identification of kappa opioid receptors in the immune system by indirect immunofluorescence. Proc Natl Acad Sci U S A 1995; 92:1062-6. [PMID: 7862634 PMCID: PMC42637 DOI: 10.1073/pnas.92.4.1062] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A method to visualize the kappa opioid receptor is described that uses a high-affinity fluorescein-conjugated opioid ligand and indirect immunofluorescence with the phycoerythrin fluorophore to amplify the signal. The mouse thymoma cell line R1E/TL8x.1.G1.OUAr.1 (R1EGO), which expresses the kappa 1 but not mu or delta opioid receptors, was used as a positive control for fluorescence labeling. A fluorescein isothiocyanate-conjugated arylacetamide (FITC-AA) compound displaying high affinity for the kappa opioid receptor was synthesized. R1EGO cells were incubated with FITC-AA, in the absence or presence of the kappa-selective opioid antagonist nor-binaltorphimine (nor-BNI) as a competitor. By using fluorescence microscopy and flow cytometry, incubation of R1EGO cells with FITC-AA alone was not sufficient for the detection of specific staining of the kappa opioid receptor. To amplify the FITC-AA fluorescence, the fluorescein served as a hapten for subsequent antibody detection. R1EGO cells were incubated with FITC-AA, followed by biotinylated rabbit anti-fluorescein IgG and extravidin-conjugated R-phycoerythrin. By using this approach, R1EGO cells were stained with phycoerythrin-amplified FITC-AA, and the staining was displaced with nor-BNI. Flow cytometry showed that titrations of both FITC-AA and nor-BNI produced saturable concentration-dependent changes in the median phycoerythrin fluorescence intensity, with optimal staining at 30 microM FITC-AA. Up to 80% of the fluorescence above background was inhibited by nor-BNI. Freshly isolated thymocytes from C57BL/6ByJ mice also showed nor-BNI-sensitive staining with the FITC-AA amplification. This sensitive method of indirect phycoerythrin immunofluorescence can be used to amplify any fluorescein-conjugated opioid ligand for the detection of opioid receptors.
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Affiliation(s)
- D M Lawrence
- Department of Pharmacology, University of Rochester, School of Medicine and Dentistry, NY 14642
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348
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Belkowski SM, Zhu J, Liu-Chen LY, Eisenstein TK, Adler MW, Rogers TJ. Detection of kappa-opioid receptor mRNA in immature T cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 373:11-6. [PMID: 7545346 DOI: 10.1007/978-1-4615-1951-5_2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The R1.1 cell line has been shown to express kappa-opioid receptors on the cell surface. Our analysis shows that the R1.1 cell line exhibits a CD4NEG CD8NEG CD3LOW CD25LOW cell surface phenotype, characteristic of thymocytes in one of the early stages of differentiation. We have developed reverse transcriptase polymerase chain reaction (RT-PCR) conditions that permit the detection of mRNA coding for the kappa-receptor. Using cell fractionation techniques we have isolated CD4NEG CD8NEG thymocytes, and analysis by RT-PCR shows that these primary immature thymocytes also express the kappa-opioid receptor. We hypothesize that the expression of kappa-opioid receptor may be a marker which is characteristic of immature T development.
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Affiliation(s)
- S M Belkowski
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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349
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Cell Surface Receptors and the G Protein-Coupled Receptor Superfamily. G PROTEIN-COUPLED RECEPTORS 1995. [DOI: 10.1007/978-3-662-21930-0_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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350
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Lai J, Bilsky EJ, Porreca F. Treatment with antisense oligodeoxynucleotide to a conserved sequence of opioid receptors inhibits antinociceptive effects of delta subtype selective ligands. J Recept Signal Transduct Res 1995; 15:643-50. [PMID: 8903970 DOI: 10.3109/10799899509045246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous work has suggested the existence of subtypes of the delta opioid receptor (DOR) which have been termed delta1 and delta2. [D-Ala2, Glu4]deltorphin has been suggested to selectively elicit antinociception via the delta2 receptor while [D-Pen2, D-Pen5]enkephalin (DPDPE) is thought to act via the delta1 receptor. Treatment with an antisense oligodeoxynucleotide (oligo) directed towards the N-terminal portion of the cloned DOR has been demonstrated to selectively inhibit the antinociceptive actions of [D-Ala2, Glu4]deltorphin, but not of DPDPE, suggesting that the cloned DOR corresponds to that pharmacologically defined as delta2. Here, an antisense oligo (or a mismatch sequence) was designed to target a conserved region of the cloned mu, delta and kappa opioid receptor. These oligos were employed in order to determine whether the antinociceptive effects of [D-Ala2, Glu4]deltorphin, as well as DPDPE, could be inhibited. The data indicate that the antinociceptive actions of both ligands were inhibited by treatment with this antisense, but not with the mismatch oligo. Taken together, the results of the treatments with oligos directed towards the N-terminal portion of the cloned DOR and with that directed to the conserved region of the opioid receptors suggest that (a) DPDPE effects are mediated by a subtype of the DOR which shares a domain common to the cloned opioid receptors, and (b) the N-terminal region differs between these putative DOR subtypes.
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MESH Headings
- Animals
- Base Sequence
- Conserved Sequence
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins/pharmacology
- Male
- Mice
- Mice, Inbred ICR
- Molecular Sequence Data
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/pharmacology
- Oligopeptides/pharmacology
- Pain Measurement
- Rats
- Receptors, Opioid, delta/classification
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/genetics
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Affiliation(s)
- J Lai
- Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA
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