Anti-psychotic and sedative effect of calcium channel blockers in mice.

Calcium channel blockers (CCBs) are widely used as therapeutic agents, for the treatment of cardiovascular disorders. However, the discovery that CCBs bind to various regions of the brain suggest that they might also offer some beneficial effects in the treatment of neuropsychiatry disorders. This study was carried out to evaluate the anti-psychotic and sedative effects of two notable calcium channel blockers, verapamil and nifedipine in mice. The anti-psychotic effects of the CCBs were studied in the animal model of amphetamine-induced stereotyped behavioral disorders. The sedative effect was assessed utilizing the prolongation of the time of sleep, induced by thiopentone. The ability of CCBs to produce catalepsy in mice was also evaluated in the study. Graded doses of verapamil (5.0-20.0 mg/kg, i.p) significantly (p<0.05) suppressed stereotyped behaviour induced by amphetamine (10.0 mg/kg, i.p). In contrast, nifedipine (5.0-20.0 mg/kg, i.p) did not exhibit anti-psychotic effect, as it could not significantly reduce stereotypy caused by amphetamine. In the test for sedation, both verapamil (5.0-20.0 mg/kg, i.p) and nifedipine (10.0-20.0 mg/kg) significantly (p<0.05) prolonged the sleeping time induced by thiopentone (50.0 mg/kg, i.p). However, neither verapamil (5.0-20.0 mg/kg, i.p.) nor nifedipine (5.0-20.0 mg/kg, i.p.) at the tested doses produced any cataleptic behaviour in the animals. The results of the study suggest that verapamil has both anti-psychotic and sedative effects without inducing the side effect of catalepsy and might be relevant in the treatment of psychosis.