C. Ratomponirina et al., SULPIRIDE, BUT NOT HALOPERIDOL, UP-REGULATES GAMMA-HYDROXYBUTYRATE RECEPTORS IN-VIVO AND IN CULTURED-CELLS, European journal of pharmacology, 346(2-3), 1998, pp. 331-337
Five days of gamma-hydroxybutyrate (GHB) administration (3 x 500 mg kg
(-1) day(-1) i.p.) to rats resulted in a significant decrease in the d
ensity of GHB receptors measured in the whole rat brain without modifi
cation of their corresponding affinity. Similar administration of (-)-
sulpiride (2 x 100 mg kg(-1) day(-1) i.p. for 5 days) induces an up-re
gulation of GHB receptors without change in their dissociation constan
ts (K-d). Haloperidol (2 x 2 mg day(-1) i.p. for 5 days) showed no eff
ect. Administered chronically via osmotic minipumps directly into the
lateral ventricles, (-)-sulpiride (60 mu g day(-1) for 7 days) and GHB
(600 mu g day(-1) for 7 days) up-regulated and down-regulated rat bra
in GHB receptors, respectively. Finally, in a mouse hybridoma cell lin
e (NCB-20 cells) expressing GHB receptors, the treatment of these cell
s with 1 mM GHB, 100 mu M (-)-sulpiride or 1 mM GABA decreases, increa
ses and induces no change, respectively, in the density of GHB recepto
rs after 3 days of treatments. These results indicate that chronic GHB
treatment modifies the expression of its receptor and that sulpiride
also induces plastic changes in GHB receptors perhaps via antagonistic
properties. (C) 1998 Elsevier Science B.V.