Effects of verapamil on electroconvulsive shock- and clonidine-induced amnesia

The effect of the Ca2+ blocker verapamil on amnesia induced by electroconvulsive shock (ECS) or by the alpha-adrenoceptor agonist clonidine was studied in male Wistar rats trained in passive avoidance task ("step down"). Clonidine (0.1 mg/kg, i.p.) and ECS induced a pronounced amnesia, significantly reducing the percentage of rats that had acquired the task upon retention tests, given 3 h, 24 h and 7 days after training. Verapamil (10 mg/kg) administered orally for 12 days (5 days before and 7 days after training) completely abolished the ECS- or clonidine-induced amnesia. These data suggest that calcium channel blocker verapamil has a protective effect against experimentally provoked memory deficit and might be useful for the treatment of cognitive disorders.