EFFECTS OF HALOPERIDOL AND GM(1) GANGLIOSIDE TREATMENT ON STRIATAL D-2 RECEPTOR-BINDING AND DOPAMINE TURNOVER

Previous studies have shown that whereas exogenous GM(1) ganglioside c o-administration leads to an increase of haloperidol-induced behaviora l supersensitivity, GM(1) significantly attenuates the behavioral para meters of dopaminergic supersensitivity when administered after abrupt haloperidol withdrawal. In the present study, the effects of GM(1) an d haloperidol co-administration (5 mg/kg GM(1) i.p. and 1 mg/kg halope ridol i.p., twice daily, for 30 days) as well as the effects of a 3 da y treatment with GM(1) were investigated in rats withdrawn from halope ridol administration by measuring striatal D-2 dopamine receptor bindi ng and dopamine turnover. The results showed that under these two expe rimental conditions GM(1) modified neither the haloperidol-induced str iatal D-2 dopamine receptor up regulation nor the decrease in dopamine turnover produced by haloperidol withdrawal These results suggest tha t the effects of GM(1) on behavioral supersensitivity are not related to modifications in dopamine receptor number or affinity and in the sy naptic availability of this catecholamine.