Background & Objective: Verapamil, nifedipine and diltiazem are calcium channel blockers widely used as a variety of cardiovascular ailment in humans. A number of studies have shown that calcium channel blockers have anticonvulsant effect in a range of animal seizure models (but not all animals). The aim of this study was to investigate the effects of verapamil, nifedipine and diltiazem on pentylenetetrazole-induced seizure threshold and to compare these effects in mice

Materials & Methods: In this experimental study, mice were pretreated intraperitoneally with vehicle or calcium channel blockers (0.5, 1, 2.5, 5, 10 and 20 mg/kg) before intravenously the determination of the pentylenetetrazole-induced seizure threshold.

Results: Our results showed that the pentylenetetrazole-induced seizure threshold was 33.4 0.42 mg/kg in control group. In animals pretreated with verapamil, nifedipine and diltiazem the pentylenetetrazole-induced seizure threshold dose dependently increased. Compare between calcium channel blockers showed that diltiazem and verapamil had greatest and least effects, respectively.

Conclusion: Our results suggest that the Ca2+ channel blockers possess anticonvulsant activity probably via an antagonism effect on voltage-gated Ca2+ channels.