Influence of calcium channel blockers on pentylenetetrazol and electroshock-induced convulsions in mice.

Nifedipine (2.5-10 mg/kg) and verapamil (2.5 and 10 mg/kg) offered some protection against pentylenetetrazol (100 and 130 mg/kg)-induced seizure activity in mice. No protection was provided by diltiazem (1.25-10 mg/kg) in this model of experimental epilepsy. Repeated administration of calcium channel blockers (CCBs) in doses of 5 and 10 mg/kg twice daily for three days resulted in no protective effect against pentylenetetrazol. Regarding electroconvulsions, nifedipine (2.5-10 mg/kg) showed the best anticonvulsive action--for instance, in the dose of 10 mg/kg (60 min--treatment time) it elevated the threshold for electroconvulsions from 7.1 to 10.5 mA. Diltiazem (up to 10 mg/kg) and verapamil (up to 20 mg/kg) were considerably less potent in this respect. After repeated administration, only nifedipine (5-10 mg/kg) retained its protective action against electroconvulsions.