Metabolic GHB precursor succinate binds to γ-hydroxybutyrate receptors: Characterization of human basal ganglia areas nucleus accumbens and globus pallidus
✍ Scribed by Tünde Molnár; Erzsébet Kútiné Fekete; Julianna Kardos; Edit Simon-Trompler; Miklós Palkovits; Zsuzsa Emri
- Book ID
- 102386341
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 359 KB
- Volume
- 84
- Category
- Article
- ISSN
- 0360-4012
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Binding of the metabolic γ‐hydroxybutyrate (GHB) precursor succinate to NCS‐382‐sensitive [^3^H]GHB‐labeled sites in crude synaptosomal or purified synaptic membrane fractions prepared from the human nucleus accumbens (NA), globus pallidus (GP) and rat forebrain has been shown. This site can be characterized by binding of ethyl hemisuccinate and gap‐junction blockers, including carbenoxolone hemisuccinate and β‐GRA. There was no significant binding interaction between GABA~B~ receptor ligands (CGP 55845, (R)‐baclofen) and these [^3^H]GHB‐labeled sites. GHB, NCS‐382 and succinate binding profile of [^3^H]GHB‐labeled sites in rat forebrain, human NA or GP synaptic membranes were similar. The synaptic fraction isolated from the rat forebrain was characterized by GHB binding inhibition constants: K~i,NCS‐382~ = 1.2 ± 0.2 μM, K~i,GHB~ = 1.6 ± 0.3 μM and K~i,SUCCINATE~ = 212 ± 66 μM. In crude membranes containing mainly extrasynaptic membranes, distinct GHB and GABA~B~ receptor sites were found in the NA. By contrast, extrasynaptic GABA~B~ receptor sites of rat forebrain and GP were GHB‐ and succinate‐sensitive, respectively. The heterogeneity of GABA~B~ sites found in native membranes indicates GABA~B~ receptor‐dependent differences in GHB action. Based on these findings, we suggest that succinate (and possibly drugs available as succinate salt derivatives) can mimic some of the actions of GHB. © 2006 Wiley‐Liss, Inc.