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Krall J, Bavo F, Falk-Petersen CB, Jensen CH, Nielsen JO, Tian Y, Anglani V, Kongstad KT, Piilgaard L, Nielsen B, Gloriam DE, Kehler J, Jensen AA, Harpsøe K, Wellendorph P, Frølund B. Discovery of 2-(Imidazo[1,2-b]pyridazin-2-yl)acetic Acid as a New Class of Ligands Selective for the γ-Hydroxybutyric Acid (GHB) High-Affinity Binding Sites. J Med Chem 2019; 62:2798-2813. [DOI: 10.1021/acs.jmedchem.9b00131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Francesco Bavo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
- Department of Pharmaceutical Sciences, University of Milan, via Mangiagalli 25, 20133 Milano, Italy
| | - Christina B. Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Claus H. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Julie O. Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Yongsong Tian
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Valeria Anglani
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kenneth T. Kongstad
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Louise Piilgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - David E. Gloriam
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jan Kehler
- Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, DK-2500 Valby, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kasper Harpsøe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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Nowaczyk A, Fijałkowski Ł, Zaręba P, Sałat K. Docking and pharmacodynamic studies on hGAT1 inhibition activity in the presence of selected neuronal and astrocytic inhibitors. Part I. J Mol Graph Model 2018; 85:171-181. [PMID: 30219588 DOI: 10.1016/j.jmgm.2018.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/11/2018] [Accepted: 09/02/2018] [Indexed: 12/30/2022]
Abstract
Inhibition of 4-aminobutanoic acid (GABA) uptake is a strategy for enhancing GABA transmission. The utility of this approach is demonstrated by the successful development of such agents for the treatment of epilepsy and pain. Existing reports on acute brain slice preparations indicate the intersecting of complementary channels and receptors sets between astrocytes and neurons cells. Thorough analysis of astroglial cells by means of molecular and functional studies demonstrated their active modulatory role in intercellular communication. The chemical interactions between sixteen GABA analogues and isoform of hGAT1 is outlined in the light of molecular docking results. In the in vivo part antinociceptive properties of racemic nipecotic acid, its R and S enantiomers and isonipecotic acid, each administered intraperitoneally at 3 fixed doses (10, 30 and 100 mg/kg), were assessed in a thermally-induced acute pain model i.e. the mouse hot plate test. Docking analyses provided complex binding energies, specific h-bond components, and h-bond properties, such as energies, distances and angles. In vivo tests revealed statistically significant antinociceptive properties of isonipecotic acid (10 and 30 mg/kg), R-nipecotic acid (30 and 100 mg/kg) and S-nipecotic acid (100 mg/kg) in mice. The docking data endorse the hypothesis of correlation between the strength of their chemical interactions with hGAT1 and analgesic action of studied compounds.
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Affiliation(s)
- Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland.
| | - Łukasz Fijałkowski
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland.
| | - Paula Zaręba
- Department of Physicochemical Drug Analysis, Chair of Pharmaceutical Chemistry, Jagiellonian University Medical College, 9 Medyczna St., 30 - 688, Krakow, Poland.
| | - Kinga Sałat
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30 - 688, Krakow, Poland.
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3
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Krall J, Jensen CH, Bavo F, Falk-Petersen CB, Haugaard AS, Vogensen SB, Tian Y, Nittegaard-Nielsen M, Sigurdardóttir SB, Kehler J, Kongstad KT, Gloriam DE, Clausen RP, Harpsøe K, Wellendorph P, Frølund B. Molecular Hybridization of Potent and Selective γ-Hydroxybutyric Acid (GHB) Ligands: Design, Synthesis, Binding Studies, and Molecular Modeling of Novel 3-Hydroxycyclopent-1-enecarboxylic Acid (HOCPCA) and trans-γ-Hydroxycrotonic Acid (T-HCA) Analogs. J Med Chem 2017; 60:9022-9039. [DOI: 10.1021/acs.jmedchem.7b01351] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacob Krall
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Claus Hatt Jensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Francesco Bavo
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Department
of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy
| | - Christina Birkedahl Falk-Petersen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Anne Stæhr Haugaard
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Stine Byskov Vogensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yongsong Tian
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Mia Nittegaard-Nielsen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Sara Björk Sigurdardóttir
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Jan Kehler
- Discovery
Chemistry, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | - Kenneth Thermann Kongstad
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - David E. Gloriam
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Rasmus Prætorius Clausen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Kasper Harpsøe
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
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4
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Monastrol, a 3,4-dihydropyrimidin-2(1 H )-thione, as structural scaffold for the development of modulators for GHB high-affinity binding sites and α 1 β 2 δ GABA A receptors. Eur J Med Chem 2017; 138:300-312. [DOI: 10.1016/j.ejmech.2017.06.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/19/2017] [Accepted: 06/14/2017] [Indexed: 11/18/2022]
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5
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Fijałkowski Ł, Sałat K, Podkowa A, Zaręba P, Nowaczyk A. Potential role of selected antiepileptics used in neuropathic pain as human GABA transporter isoform 1 (GAT1) inhibitors-Molecular docking and pharmacodynamic studies. Eur J Pharm Sci 2016; 96:362-372. [PMID: 27721044 DOI: 10.1016/j.ejps.2016.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 01/31/2023]
Abstract
The chemical interaction of nine antiepileptic drugs (tiagabine, gabapentin, pregabalin, lamotrigine, zonisamide, valproic acid, valpromide, vigabatrin, progabide) and two endogenous metabolites (4-aminobutanoic acid, 4-hydroxybutanoic acid) with a model of human GABA transporter 1 (hGAT1) is described using the molecular docking method. To establish the role of hGAT1 in chronic pain, tiagabine, a selective hGAT1 inhibitor, was assessed in the in vivo experiments for its antiallodynic properties in two mouse models of neuropathic pain. Docking analyses performed in this study provided the complex binding energies, specific hydrogen bond components, and hydrogen bond properties such as energies, distances and angles. The data of the docking studies strongly support the assumption that the antiepileptic and analgesic actions of the studied drugs can be at least in part related to the strength of their chemical interactions with hGAT1. In vivo experiments with tiagabine confirmed the involvement of hGAT1 in the regulation of the mechanical nociceptive threshold in neuropathic pain.
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Affiliation(s)
- Łukasz Fijałkowski
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
| | - Kinga Sałat
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Cracow, Poland
| | - Adrian Podkowa
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Cracow, Poland
| | - Paula Zaręba
- Department of Physicochemical Drug Analysis, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Cracow, Poland
| | - Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland.
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6
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GHB receptor targets in the CNS: Focus on high-affinity binding sites. Biochem Pharmacol 2014; 87:220-8. [DOI: 10.1016/j.bcp.2013.10.028] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/29/2013] [Accepted: 10/29/2013] [Indexed: 12/13/2022]
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7
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Elie MP, Baron MG, Birkett JW. Injection port silylation of γ-hydroxybutyrate and trans-hydroxycrotonic acid: conditions optimisation and characterisation of the di-tert-butyldimethylsilyl derivatives by GC-MS. Analyst 2011; 137:255-62. [PMID: 22081086 DOI: 10.1039/c1an15825b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Silylation is usually carried out on γ-hydroxybutyrate (GHB) for its analysis by Gas Chromatography/Mass Spectrometry (GCMS) and requires potentially long incubation times before injection during which the derivatisation reagent and derivatives (such as trimethyl-silyl compounds) can hydrolyse. Moreover, alternative internal standards (IS) are often useful depending on sample matrices, extraction/purification procedures, commercial availability and price. This study evaluated the possibility of silylating GHB with an injection port derivatisation procedure using N-methyl-N-[tert-butyldimethyl-silyl]trifluoroacetimide (MTBSTFA) with 1% tert-butyldimethylchlorosilane (TBCS) as the derivatisation reagent, producing di-tert-butyldimethyl-silyl derivatives as a novel means of analyzing GHB. In parallel, trans-hydroxycrotonic acid (t-HCA) was investigated as a potential IS for GHB quantification. Analyses were carried out with a temperature programmable injector and the GHB(t-BDMS)(2) and t-HCA(t-BDMS)(2) derivatives were successfully produced, characterised and derivatisation conditions optimised. t-HCA behaved very similarly to GHB through the derivatisation processes and was used as the IS for the determination of urinary endogenous GHB concentrations in human subjects where the method showed a limit of detection of 0.049 μg mL(-1), a limit of quantification of 0.162 μg mL(-1), and a limit of confirmation of 1.33 μg mL(-1), suitable for toxicological GHB concentration determination.
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Affiliation(s)
- Mathieu Pierre Elie
- School of Life Science, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK.
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8
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Coune P, Taleb O, Mensah-Nyagan AG, Maitre M, Kemmel V. Calcium and cAMP signaling induced by gamma-hydroxybutyrate receptor(s) stimulation in NCB-20 neurons. Neuroscience 2010; 167:49-59. [PMID: 20153403 DOI: 10.1016/j.neuroscience.2010.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 02/03/2010] [Accepted: 02/03/2010] [Indexed: 10/19/2022]
Abstract
The NCB-20 neurohybridoma cells differentiated with dibutyryl-cyclic-AMP represent an interesting model to study several components of the gamma-hydroxybutyrate (GHB) system in brain. In particular, an active Na(+)-dependent uptake and a depolarization-evoked release of GHB is expressed by these cells, together with high affinity specific binding sites for this substance. However, only little is known about cellular mechanisms following GHB receptor(s) stimulation in these neurons. Electrophysiological data indicate that GHB can differently affect Ca(2+) currents. L-type calcium channels were typically inhibited by GHB when NCB-20 cells were depolarized. In contrast, when NCB-20 cells were at resting potential, GHB induced a specific Ca(2+) entry through T-type calcium channels. In this study, we investigated the effect induced on cytosolic free Ca(2+) level and cAMP production by GHB receptor(s) stimulated with micromolar concentrations of GHB or structural analogues of GHB. Ca(2+) movements studied by cellular imaging were dose-dependently increased but disappeared for GHB concentrations >25 microM. In addition, nanomolar doses of GHB inhibited forskolin-stimulated adenylate cyclase. This effect was also rapidly desensitized at higher GHB concentrations. Acting as an antagonist, NCS-382 decreased GHB receptor(s) mediated cAMP and calcium signals. The agonist NCS-356 mimicked GHB effects which were not affected by the GABA(B) receptor antagonist CGP-55-845. Our results reveal the occurrence of Ca(2+)-dependent adenylate cyclase inhibition in NCB-20 neurons after GHB receptor(s) stimulation by GHB concentrations <50 microM. Above this dose, GHB effects were inactivated. In addition, at GHB concentrations exceeding 50 microM, GTP-gammaS binding was also reduced, confirming the desensitization of GHB receptor(s). Taken together, these results support the existence in NCB-20 neurons of GHB receptors belonging to GPCR family that may recruit various G protein subtypes.
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Affiliation(s)
- P Coune
- Equipe Stéroïdes, Neuromodulateurs et Neuropathologies, Unité de Physiopathologie et Médecine Translationnelle, EA-4438, Faculté de médecine, Université de Strasbourg, Strasbourg, France
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9
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Wellendorph P, Høg S, Skonberg C, Bräuner-Osborne H. Phenylacetic acids and the structurally related non-steroidal anti-inflammatory drug diclofenac bind to specific gamma-hydroxybutyric acid sites in rat brain. Fundam Clin Pharmacol 2009; 23:207-13. [PMID: 19645815 DOI: 10.1111/j.1472-8206.2008.00664.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Gamma-Hydroxybutyric acid (GHB) is a proposed neurotransmitter or neuromodulator with a yet unresolved mechanism of action. GHB binds to both specific high-affinity GHB binding sites and to gamma-aminobutyric acid subtype B (GABA(B)) receptors in the brain. To separate specific GHB effects from GABA(B) receptor effects, it is imperative to develop GHB selective and potent compounds. We generated the compound, 4-(biphen-4-yl)-4-hydroxybutyric acid, which is the 4-hydroxyl analogue of the non-steroidal anti-inflammatory drug (NSAID) fenbufen (referred to as gamma-hydroxyfenbufen). When measured in a rat brain homogenate [(3)H]NCS-382 binding assay, gamma-hydroxyfenbufen inhibited [(3)H]NCS-382 binding with a 10-fold higher affinity than GHB (K(i) 0.44 microM), thus establishing it as a novel lead structure. The active metabolite of fenbufen, 4-biphenylacetic acid inhibited [(3)H]NCS-382 binding with a twofold higher affinity than GHB. Measuring the affinities of structurally related NSAIDs for the [(3)H]NCS-382 site identified diclofenac, a clinically relevant NSAID (Voltaren, Diclon) of the phenylacetic acid (PAA) type, as a GHB ligand (K(i) value of 5.1 microM). Other non-NSAID PAAs also exhibited affinities similar to GHB. Our data raise the interesting possibility that the widely used over-the-counter drug compound, diclofenac, might affect GHB binding at relevant clinical dosages. Furthermore, the identification of PAAs as GHB ligands supplies new information about the structural preferences of the GHB ligand-binding site.
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Affiliation(s)
- Petrine Wellendorph
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark.
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10
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Høg S, Wellendorph P, Nielsen B, Frydenvang K, Dahl IF, Bräuner-Osborne H, Brehm L, Frølund B, Clausen RP. Novel high-affinity and selective biaromatic 4-substituted gamma-hydroxybutyric acid (GHB) analogues as GHB ligands: design, synthesis, and binding studies. J Med Chem 2009; 51:8088-95. [PMID: 19053823 DOI: 10.1021/jm801112u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gamma-hydroxybutyrate (GHB) is a metabolite of gamma-aminobutyric acid (GABA) and has been proposed to function as a neurotransmitter or neuromodulator. GHB is used in the treatment of narcolepsy and is a drug of abuse. GHB binds to both GABA(B) receptors and specific high-affinity GHB sites in brain, of which the latter have not been linked unequivocally to function, but are speculated to be GHB receptors. In this study, a series of biaromatic 4-substituted GHB analogues, including 4'-phenethylphenyl, 4'-styrylphenyl, and 4'-benzyloxyphenyl GHB analogues, were synthesized and characterized pharmacologically in a [3H](E,RS)-(6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylidene)acetic acid ([3H]NCS-382) binding assay and in GABA(A) and GABA(B) receptor binding assays. The compounds were selective for the high-affinity GHB binding sites and several displayed Ki values below 100 nM. The affinity of the 4-[4'-(2-iodobenzyloxy)phenyl] GHB analogue 17b was shown to reside predominantly with the R-enantiomer (Ki = 22 nM), which has higher affinity than previously reported GHB ligands.
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Affiliation(s)
- Signe Høg
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2 Universitetsparken, DK-2100 Copenhagen, Denmark
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11
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Carter LP, Koek W, France CP. Behavioral analyses of GHB: receptor mechanisms. Pharmacol Ther 2008; 121:100-14. [PMID: 19010351 DOI: 10.1016/j.pharmthera.2008.10.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 10/14/2008] [Indexed: 11/25/2022]
Abstract
GHB is used therapeutically and recreationally, although the precise mechanism of action responsible for its different behavioral effects is not entirely clear. The purpose of this review is to summarize how behavioral procedures, especially drug discrimination procedures, have been used to study the mechanism of action of GHB. More specifically, we will review several different drug discrimination procedures and discuss how they have been used to qualitatively and quantitatively study different components of the complex mechanism of action of GHB. A growing number of studies have provided evidence that the behavioral effects of GHB are mediated predominantly by GABAB receptors. However, there is also evidence that the mechanisms mediating the effects of GHB and the prototypical GABAB receptor agonist baclofen are not identical, and that other mechanisms such as GHB receptors and subtypes of GABAA and GABAB receptors might contribute to the effects of GHB. These findings are consistent with the different behavioral profile, abuse liability, and therapeutic indications of GHB and baclofen. A better understanding of the similarities and differences between GHB and baclofen, as well as the pharmacological mechanisms of action underlying the recreational and therapeutic effects of GHB, could lead to more effective medications with fewer adverse effects.
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Anderson IB, Kim SY, Dyer JE, Burkhardt CB, Iknoian JC, Walsh MJ, Blanc PD. Trends in gamma-hydroxybutyrate (GHB) and related drug intoxication: 1999 to 2003. Ann Emerg Med 2005; 47:177-83. [PMID: 16431231 PMCID: PMC2246009 DOI: 10.1016/j.annemergmed.2005.10.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 06/20/2005] [Accepted: 10/13/2005] [Indexed: 11/22/2022]
Abstract
STUDY OBJECTIVE To analyze changes in gamma-hydroxybutyrate (GHB) case reporting, we review GHB or congener drug cases reported to the California Poison Control System, comparing these to other data sets. METHODS We identified cases from the California Poison Control System computerized database using standardized codes and key terms for GHB and congener drugs ("gamma butyrolactone," "1,4-butanediol," "gamma valerolactone"). We noted California Poison Control System date, caller and exposure site, patient age and sex, reported coingestions, and outcomes. We compared California Poison Control System data to case incidence from American Association of Poison Control Centers and Drug Abuse Warning Network data and drug use prevalence from National Institute for Drug Abuse survey data. RESULTS A total of 1,331 patients were included over the 5-year period (1999-2003). California Poison Control System-reported GHB exposures decreased by 76% from baseline (n=426) to the final study year (n=101). The absolute decrease was present across all case types, although there was a significant proportional decrease in routine drug abuse cases and an increase in malicious events, including GHB-facilitated sexual assault (P=.002). American Association of Poison Control Centers data showed a similar decrease from 2001 to 2003. Drug Abuse Warning Network incidence flattened from 2001 to 2002 and decreased sharply in 2003. National Institute for Drug Abuse survey time trends were inconsistent across age groups. CONCLUSION Based on the precipitous decrease in California Poison Control System case incidence for GHB during 5 years, the parallel trend in American Association of Poison Control Centers data, and a more recent decrease in Drug Abuse Warning Network cases, a true decrease in case incidence is likely. This could be due to decreased abuse rates or because fewer abusers seek emergency medical care. Case reporting may account for part of the decrease in the incidence of poison center contacts involving GHB.
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Affiliation(s)
- Ilene B Anderson
- California Poison Control System, Department of Clinical Pharmacy, University of California, San Francisco, CA, USA.
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13
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Chen W, Wu H, Hernandez RJ, Mehta AK, Ticku MK, France CP, Coop A. Ethers of 3-hydroxyphenylacetic acid as selective gamma-hydroxybutyric acid receptor ligands. Bioorg Med Chem Lett 2005; 15:3201-2. [PMID: 15927467 DOI: 10.1016/j.bmcl.2005.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 04/26/2005] [Accepted: 05/03/2005] [Indexed: 10/25/2022]
Abstract
Gamma-hydroxybutyric acid (GHB) is a drug of abuse, a therapeutic, and purportedly a neurotransmitter with a complex mechanism of action in vivo due to direct actions at GABA(B) as well as GHB receptors and because of its metabolism to GABA. Herein, we describe 3-ethers of 3-hydroxyphenylacetic acid, which have relatively high affinity at GHB sites, no significant affinity at GABA receptors, and would not be expected to be rapidly metabolized to GABAergic ligands. The selectivity of these compounds (UMB108, UMB109, and UMB119) could prove to be useful for studying the biology of GHB receptors, free from GABAergic effects.
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Affiliation(s)
- Weibin Chen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Room 637, Baltimore, MD 21201, USA
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14
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Wellendorph P, Høg S, Greenwood JR, de Lichtenberg A, Nielsen B, Frølund B, Brehm L, Clausen RP, Bräuner-Osborne H. Novel cyclic gamma-hydroxybutyrate (GHB) analogs with high affinity and stereoselectivity of binding to GHB sites in rat brain. J Pharmacol Exp Ther 2005; 315:346-51. [PMID: 16014570 DOI: 10.1124/jpet.105.090472] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gamma-hydroxybutyrate (GHB) is a psychotropic compound endogenous to the brain. Despite its potentially great physiological significance, its exact molecular mechanism of action is unknown. GHB is a weak agonist at GABA(B) receptors, but there is also evidence of specific GHB receptor sites, the molecular cloning of which remains a challenge. Ligands with high affinity and specificity for the reported GHB binding site are needed for pharmacological dissection of the GHB and GABA(B) effects and for mapping the structural requirements of the GHB receptor-ligand interactions. For this purpose, we have synthesized and assayed three conformationally restricted GHB analogs for binding against the GHB-specific ligand [3H]NCS-382 [(E,RS)-(6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylidene-)acetic acid] in rat brain homogenate. The cyclohexene and cyclopentene analogs, 3-hydroxycyclohex-1-enecarboxylic acid [(RS)-HOCHCA] and 3-hydroxycyclopent-1-enecarboxylic acid [(RS)-HOCPCA], were found to be high-affinity GHB ligands, with IC50 values in the nanomolar range, and had 9 and 27 times, respectively, higher affinity than GHB. The stereo-selectively synthesized R,R-isomer of the trans-cyclopropyl GHB analog, HOCPrCA, proved to have 10-fold higher affinity than its enantiomer. Likewise, the R-enantiomers of HOCHCA and HOCPCA selectively inhibited [3H]NCS-382 binding. The best inhibitor of these, (R)-HOCPCA, has an affinity 39 times higher than GHB and is thus among the best GHB ligands reported to date. Neither of the cycloalkenes showed any affinity (IC50 > 1 mM) for GABA(A) or GABA(B) receptors. These compounds show excellent potential as lead structures and novel tools for studying specific GHB receptor-mediated pharmacology.
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Affiliation(s)
- Petrine Wellendorph
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Copenhagen, Denmark
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Pistis M, Muntoni AL, Pillolla G, Perra S, Cignarella G, Melis M, Gessa GL. Gamma-hydroxybutyric acid (GHB) and the mesoaccumbens reward circuit: evidence for GABA(B) receptor-mediated effects. Neuroscience 2005; 131:465-74. [PMID: 15708487 DOI: 10.1016/j.neuroscience.2004.11.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2004] [Indexed: 10/25/2022]
Abstract
Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid naturally occurring in the mammalian brain, which recently emerged as a major recreational drug of abuse. GHB has multiple neuronal mechanisms including activation of both the GABA(B) receptor, and a distinct GHB-specific receptor. This complex GHB-GABA(B) receptor interaction is probably responsible for the multifaceted pharmacological, behavioral and toxicological profile of GHB. Drugs of abuse exert remarkably similar effects upon reward-related circuits, in particular the mesolimbic dopaminergic system and the nucleus accumbens (NAc). We used single unit recordings in vivo from urethane-anesthetized rats to characterize the effects of GHB on evoked firing in NAc "shell" neurons and on spontaneous activity of antidromically identified dopamine (DA) cells located in the ventral tegmental area. GHB was studied in comparison with the GABA(B) receptor agonist baclofen and antagonist (2S)(+)-5,5-dimethyl-2-morpholineacetic acid (SCH50911). Additionally, we utilized a GHB analog, gamma-(p-methoxybenzil)-gamma-hydroxybutyric acid (NCS-435), devoid of GABA(B) binding properties, but with high affinity for specific GHB binding sites. In common with other drugs of abuse, GHB depressed firing in NAc neurons evoked by the stimulation of the basolateral amygdala. On DA neurons, GHB exerted heterogeneous effects, which were correlated to the baseline firing rate of the cells but led to a moderate stimulation of the DA system. All GHB actions were mediated by GABA(B) receptors, since they were blocked by SCH50911 and were not mimicked by NCS-435. Our study indicates that the electrophysiological profile of GHB is close to typical drugs of abuse: both inhibition of NAc neurons and moderate to strong stimulation of DA transmission are distinctive features of diverse classes of abused drugs. Moreover, it is concluded that addictive and rewarding properties of GHB do not necessarily involve a putative high affinity GHB receptor.
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Affiliation(s)
- M Pistis
- B. B. Brodie Department of Neuroscience, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
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Carter LP, Wu H, Chen W, Matthews MM, Mehta AK, Hernandez RJ, Thomson JA, Ticku MK, Coop A, Koek W, France CP. Novel gamma-hydroxybutyric acid (GHB) analogs share some, but not all, of the behavioral effects of GHB and GABAB receptor agonists. J Pharmacol Exp Ther 2005; 313:1314-23. [PMID: 15769868 DOI: 10.1124/jpet.104.077578] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
gamma-Hydroxybutyrate (GHB), a therapeutic for narcolepsy and a drug of abuse, has several mechanisms of action that involve GHB and GABA(B) receptors, metabolism to GABA, and modulation of dopaminergic signaling. The aim of these studies was to examine the role of GHB and GABA(B) receptors in the behavioral effects of GHB. Three approaches were used to synthesize GHB analogs that bind selectively to GHB receptors and are not metabolized to GABA-active compounds. Radioligand binding assays identified UMB86 (4-hydroxy-4-napthylbutanoic acid, sodium salt), UMB72 [4-(3-phenylpropyloxy)butyric acid, sodium salt], UMB73 (4-benzyloxybutyric acid, sodium salt), 2-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid (3-HPA), and 4-hydroxy-4-phenylbutyric acid as compounds that displace [(3)H]NCS-382 [5-[(3)H]-(2E)-(5-hydroxy-5,7,8,9-tetrahydro-6H-benzo[a][7] annulen-6-ylidene) ethanoic acid] from GHB receptors at concentrations that do not markedly affect [(3)H]GABA binding to GABA(B) receptors. In rats and pigeons, GHB discriminative stimulus effects were not mimicked or attenuated by UMB86, UMB72, or 3-HPA up to doses that decreased responding. In mice, GHB, GHB precursors (gamma-butyrolactone and 1,4-butanediol) and GABA(B) receptor agonists [SKF97541 [3-aminopropyl(methyl)phosphinic acid hydrochloride] and baclofen] dose-dependently produced hypolocomotion, catalepsy, ataxia, and loss of righting. The GABA(B) receptor antagonist CGP35348 (3-aminopropyl(diethoxymethyl)phosphinic acid) attenuated catalepsy and ataxia that was observed after GHB and GABA(B) receptor agonists SKF97541 and baclofen. UMB86, UMB72, UMB73, and 3-HPA, like GHB, produced hypolocomotion, ataxia, and loss of righting; however, catalepsy was never observed with these compounds, which is consistent with the cataleptic effects of GHB being mediated by GABA(B) receptors. Ataxia that was observed with UMB86, UMB72, UMB73, and 3-HPA was not antagonized by CGP35348, suggesting that ataxia induced by these analogs is not mediated by GABA(B) receptors and might involve GHB receptors.
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Affiliation(s)
- Lawrence P Carter
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, 78229-3900, USA
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Castelli MP, Pibiri F, Carboni G, Piras AP. A review of pharmacology of NCS-382, a putative antagonist of gamma-hydroxybutyric acid (GHB) receptor. CNS DRUG REVIEWS 2004; 10:243-60. [PMID: 15492774 PMCID: PMC6741708 DOI: 10.1111/j.1527-3458.2004.tb00025.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gamma-hydroxybutyric acid (GHB), a naturally occurring metabolite of gamma-aminobutyric acid (GABA), has been postulated to act as a specific agonist of GHB receptors and as well as a weak GABA(B) receptor agonist. To date, 6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylideneacetic acid (NCS-382), a semirigid compound structurally related to GHB, is the only compound reported to be an antagonist of the GHB receptor sites. In this article we review the in vivo and in vitro pharmacological properties of NCS-382 and its interaction with GHB and GABA(B) receptors. Binding studies have demonstrated that NCS-382 is a stereoselective ligand for GHB-binding sites, with both, the high and the low component of population, showing the same distribution of GHB receptors. Indeed, this compound did not display affinity for GABA(A), GABA(B), or any other known receptors, while conflicting data have been reported as to its selective antagonist action at GHB receptor. Only a few studies have shown that NCS-382 antagonizes GHB-induced effect, but a re-evaluation of all data reported in the literature suggests that the antagonistic effect of this compound could be due to an indirect action at GABA(B) receptors. As revealed by several behavioral studies, NCS-382 fails to antagonize GHB discriminative stimuli, GHB-induced inhibition of locomotor activity and ataxia or suppression of operant responses. Moreover, it is capable of either eliciting qualitatively similar effects to those of GHB or enhancing some actions of GHB. In addition, the NCS-382-sensitive electrophysiological effects of endogenous and exogenous GHB observed in vivo have not been completely replicated in vitro. The only electrophysiological action of GHB antagonized in vitro by NCS-382 required a previous blockade of GABA(B) receptors. We concluded that NCS-382 is a good ligand but not a selective antagonist for GHB receptor.
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Affiliation(s)
- M Paola Castelli
- B. B. Brodie Department of Neuroscience, University of Cagliari, 09042 Monserrato (CA) Italy.
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Macias AT, Hernandez RJ, Mehta AK, MacKerell AD, Ticku MK, Coop A. 3-chloropropanoic acid (UMB66): a ligand for the gamma-hydroxybutyric acid receptor lacking a 4-hydroxyl group. Bioorg Med Chem 2004; 12:1643-7. [PMID: 15028257 DOI: 10.1016/j.bmc.2004.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 01/08/2004] [Accepted: 01/17/2004] [Indexed: 11/17/2022]
Abstract
Gamma-Hydroxybutyric acid (GHB) has gained in notoriety in recent years due to its association with sexual assaults. GHB is an endogenous ligand for GHB receptors, but its complete pharmacological mechanism of action in vivo remains unclear due to apparent GABAergic components. It has been proposed that the hydroxyl group in the 4-position acts as a hydrogen bond donor to the GHB receptor. Herein we show that 3-chloropropanoic acid possesses significant affinity for the GHB receptor, has no affinity for GABA receptors, and cannot undergo metabolism to GABAergic compounds. UMB66 is thus a selective agent for the study of GHB in vivo. These results, in combination with data from quantum mechanical calculations, suggest that the hydroxyl group of GHB actually acts as a hydrogen bond acceptor in contrast to the currently accepted model. This finding is anticipated to facilitate the rational design of novel agents with selectivity for GHB receptors that may be used to elucidate the mechanism of action of this common drug of abuse.
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Affiliation(s)
- Alba T Macias
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Room 637, Baltimore, MD 21201, USA
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Castelli MP, Ferraro L, Mocci I, Carta F, Carai MAM, Antonelli T, Tanganelli S, Cignarella G, Gessa GL. Selective gamma-hydroxybutyric acid receptor ligands increase extracellular glutamate in the hippocampus, but fail to activate G protein and to produce the sedative/hypnotic effect of gamma-hydroxybutyric acid. J Neurochem 2003; 87:722-32. [PMID: 14535954 DOI: 10.1046/j.1471-4159.2003.02037.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two gamma-hydroxybutyric acid (GHB) analogues, trans-gamma-hydroxycrotonic acid (t-HCA) and gamma-(p-methoxybenzyl)-gamma-hydroxybutyric acid (NCS-435) displaced [3H]GHB from GHB receptors with the same affinity as GHB but, unlike GHB, failed to displace [3H]baclofen from GABAB receptors. The effect of the GHB analogues, GHB and baclofen, on G protein activity and hippocampal extracellular glutamate levels was compared. While GHB and baclofen stimulated 5'-O-(3-[35S]thiotriphospate) [35S]GTPgammaS binding both in cortex homogenate and cortical slices, t-HCA and NCS-435 were ineffective up to 1 mm concentration. GHB and baclofen effect was suppressed by the GABAB antagonist CGP 35348 but not by the GHB receptor antagonist NCS-382. Perfused into rat hippocampus, 500 nm and 1 mm GHB increased and decreased extracellular glutamate levels, respectively. GHB stimulation was suppressed by NCS-382, while GHB inhibition by CGP 35348. t-HCA and NCS-435 (0.1-1000 microm) locally perfused into hippocampus increased extracellular glutamate; this effect was inhibited by NCS-382 (10 microm) but not by CGP 35348 (500 microm). The results indicate that GHB-induced G protein activation and reduction of glutamate levels are GABAB-mediated effects, while the increase of glutamate levels is a GHB-mediated effect. Neither t-HCA nor NCS-435 reproduced GHB sedative/hypnotic effect in mice, confirming that this effect is GABAB-mediated. The GHB analogues constitute important tools for understanding the physiological role of endogenous GHB and its receptor.
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Andriamampandry C, Taleb O, Viry S, Muller C, Humbert JP, Gobaille S, Aunis D, Maitre M. Cloning and characterization of a rat brain receptor that binds the endogenous neuromodulator gamma-hydroxybutyrate (GHB). FASEB J 2003; 17:1691-3. [PMID: 12958178 DOI: 10.1096/fj.02-0846fje] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gamma-hydroxybutyrate (GHB) is an endogenous neuromodulator with therapeutical applications in anesthesia, sleep disorders, and drug addiction. We report the cloning of a GHB receptor from a rat hippocampal cDNA library. This receptor has a molecular mass of 56 kDa and belongs to the seven-transmembrane receptor family. The peptidic sequence has no significant homology with any known receptor, including GABA(B) receptors. Its mRNA is restricted to the brain and is particularly abundant in the hippocampus, cortex, striatum, thalamus, olfactory bulbs, and cerebellum, matching the distribution of GHB binding sites in rat brain. Southern blot revealed the presence of homologous sequences in several species including the human. Binding assays on transfected CHO cells showed a dissociation constant (Kd) of 426 nM for GHB and no affinity for GABA, baclofen, or glutamate. In patch-clamp experiments, transfected CHO cells revealed a functional G-protein-coupled receptor as demonstrated by GTP-gamma-S-induced irreversible activation. Application of 0.1-15 microM GHB specifically induced an inward current at negative membrane potentials that was not reproduced by application of baclofen (10 microM). CGP-55845, a GABA(B) receptor antagonist, did not inhibit the GHB-induced response nor did the GHB receptor antagonist NCS-382, suggesting that the GHB receptor system includes several subtypes.
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Affiliation(s)
- Christian Andriamampandry
- Institut de Chimie Biologique and INSERM U-575, Faculté de Médecine, 11 rue Humann, 67085 Strasbourg cedex, France
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Wu H, Zink N, Carter LP, Mehta AK, Hernandez RJ, Ticku MK, Lamb R, France CP, Coop A. A tertiary alcohol analog of gamma-hydroxybutyric acid as a specific gamma-hydroxybutyric acid receptor ligand. J Pharmacol Exp Ther 2003; 305:675-9. [PMID: 12606613 DOI: 10.1124/jpet.102.046797] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
gamma-Hydroxybutyric acid (GHB) shows great promise as a treatment for sleeping disorders but is also increasingly abused. The exact mechanism of action of GHB is yet to be delineated, but it is known to interact with specific GHB binding sites or receptors, to act as a weak agonist at GABA(B) receptors, and that GHB undergoes metabolism to GABA. In drug discrimination studies, GABA(B) agonists, and to a lesser extent GABA(A)-positive modulators, substitute for GHB. To delineate the relative contributions of each receptor system to the profile of GHB, tertiary alcohol analogs of GHB and its homolog, 5-hydroxypentanoic acid (UMB58), were prepared (UMB68 and UMB75, respectively), which cannot be metabolized to GABA-active compounds. Binding studies against [(3)H]NCS-382 [(2E)-(5-hydroxy-5,7,8,9-tetrahydro-6H-benzo[a][7]annulen-6-ylidene) ethanoic acid] showed that the tertiary alcohol analog of GHB (UMB68) has similar affinity to GHB, with the longer chain analogs possessing lower affinity. Against [(3)H]GABA, UMB68 showed no affinity (IC(50) >100 microM) at GABA(A) or GABA(B) receptors. In vivo studies showed that, at behaviorally active doses, rats trained to discriminate GHB did not recognize the novel ligands as GHB. Thus, UMB68 is a selective GHB receptor ligand in binding assays, will not undergo metabolism to GABA-active compounds, and does not show the same effects as GHB in vivo. These data suggest that, although UMB68 binds to the GHB receptor, it does not have the observed GABA receptor-mediated effects of GHB in vivo and could provide a novel tool for studying the pharmacology of the GHB receptor in the absence of complicating GABAergic effects.
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Affiliation(s)
- Huifang Wu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 North Pine Street, Baltimore, MD 21201, USA
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