EFFECT OF DIHYDROPYRIDINE CA2+ CHANNEL BLOCKERS ON PTZ-INDUCED CLONIC SEIZURE THRESHOLD IN MICE

iAbstract Background: Several studies have shown that the dihydropyridine calcium channel blockers such as nimodipine, nifedipine, and amlodipine have anticonvulsant effect in a range of animal models. Objective: The aim of this study was to investigate the effects of nimodipine, nifedipine and amlodipine on PTZ-induced seizure threshold with further comparison of results in mice. Methods: In 2007, this experimental study was carried out in School of Veterinary Medicine of Tabriz Islamic Azad University. Male NMRI mice were randomly divided into groups of ten members. Mice were intraperitoneally pretreated with vehicle or dihydropyridines (0.5-20 mg/kg) before the determination of intravenously PTZ-induced seizure threshold. Findings: The PTZ seizure threshold was 33.4±0.42 mg/kg in control group. In animals pretreated with nimodipine, nifedipine and amlodipine, the PTZ seizure threshold dose-dependently increased, compared with vehicle group. Nimodipine and nifedipine were found to have the highest and lowest anticonvulsant effects, respectively. Conclusion: Our results suggest that the dihydropyridine Ca 2+ channel blockers induce an anticonvulsant activity probably via an antagonistic effect on voltage-gated Ca 2+ channels.