5-HT1A receptors are not involved in clozapine's lack of cataleptogenic potential

Clozapine and 8-OH-DPAT antagonized haloperidol-induced catalepsy in rats (ED(50) 10 and 0.1 mg/kg s.c., respectively). Whereas the selective 5-HT1A receptor antagonist WAY 100635 (0.1 mg/kg s.c.) completely antagonized the inhibitory effect of 8-OH-DPAT, clozapine's effect was not affected. On the other hand, clozapine and 8-OH-DPAT inhibited ultrasonic vocalization in rats (ED(50) 0.7 and 0.03 mg/kg s.c., respectively), which effects were antagonized by WAY 100635. The lack of catalepsy of clozapine, therefore, cannot be addressed primarily to clozapine's agonistic activity at 5-HT1A receptors. Copyright (C) 1996 Elsevier Science Ltd.