title: Cloning and characterization of a rat brain receptor that binds the endogenous neuromodulator gamma-hydroxybutyrate (GHB).
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.
authors.affiliation: Institut de Chimie Biologique and INSERM U-575, Faculté de Médecine, 11 rue Humann, 67085 Strasbourg cedex, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Andriamampandry
authors.forename: Omar
authors.initials: O
authors.lastname: Taleb
authors.forename: Sandrine
authors.initials: S
authors.lastname: Viry
authors.forename: Claude
authors.initials: C
authors.lastname: Muller
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Humbert
authors.forename: Serge
authors.initials: S
authors.lastname: Gobaille
authors.forename: Dominique
authors.initials: D
authors.lastname: Aunis
authors.forename: Michel
authors.initials: M
authors.lastname: Maitre
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D006801:Humans; D018408:Patch-Clamp Techniques; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012978:Sodium Oxybate / Q000378:metabolism*; D014162:Transfection
chemical_list: C039403:4-hydroxybutyric acid receptor; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D012978:Sodium Oxybate