Dotarizine (DOT), a compound performing both as calcium antagonist and as 5-HT2 receptor antagonist, was evaluated for its ability to protect against electroconvulsive shock (ECS)- and pentylenetetrazol (PTZ)-induced performance deficit in a passive avoidance "step-down" task in rats. Its effect on electric and PTZ seizure models was also studied. DOT administered orally at a dose of 50 mg/kg for 5 days before learning had no significant effect on retention tests given 3 h, 24 h and 7 days after the training session. It should be noted, however, that DOT completely prevented ECS- and PTZ-induced amnesia in passive avoidance situation. DOT had a pronounced protective effect against electric seizures but did not affect PTZ seizures. The present results provide additional evidence for the role of serotonergic neurotransmitter system and calcium homeostasis for memory and seizure reactivity and may be important in the development of effective treatment strategies for memory dysfunction.