Haloperidol-induced catalepsy is influenced by calcium channel antagonists.

The effect of pretreatment of some voltage-dependent calcium channel antagonists was studied on haloperidol-induced catalepsy in male Wistar rats. Cataleptogenic effect of haloperidol (0.25 mg/kg, i.p.) was enhanced dose-dependently by nitrendipine (5, 10 and 20 mg/kg, i.p.) and the highest dose of nimodipine (20 mg/kg, i.p.). Neither verapamil (10 and 20 mg/kg, i.p.) nor diltiazem (10 and 20 mg/kg, i.p.) influenced the score of haloperidol-induced catalepsy in rats. These results suggest the involvement of calcium-dependent mechanisms in the generation of haloperidol-induced catalepsy. The possible involvement of dopaminergic mechanisms and modification by calcium channel antagonists are discussed.