POSSIBLE INVOLVEMENT OF GABAA RECEPTOR SITES IN CATALEPSY

The present work was performed to show the possible interaction of GAB A, and GABAB receptors in catalepsy. The following results were obtained: 1- Muscimol (MUS), a GABAA agonist, induced catalepsy. This effect was dose-dependent. Baclofen (BAC), a GABAB agonist, had no effect in this respect. 2- Catalepsy induced by muscimol was potentiated by pretreatment of animals with bicuculline (BIC), a GABAA antagonist, while pretreatment of animals with picrotoxin (PIC), another GABAA antagonist, did not change the response. 3- The cataleptogenic effect of a-flupenthixol (a-FPT), a neuroleptic which is a potent cataleptogenic drug, was also increased by bicuculline pretreatment. Aflupenthixol, in animals pretreated with picrotoxin, induced a small but significant increase in catalepsy. 4- Muscimol catalepsy may be due to GABA inhibitory effect of the drug upon dopaminergic function, while potentiation of cataleptogenic effect of a-flupenthixol or that of muscimol by bicuculline may be exerted through release of GABA from GABAergic nerve endings