EFFECTS OF NIMODIPINE, FELODIPINE AND AMLODIPINE ON ELECTROCONVULSIVESHOCK-INDUCED AMNESIA IN THE RAT

The effects of various doses (0.03, 0.1, 0.3 or 1.0 mg/kg) of the Ca2 channel blockers nimodipine, felodipine and amlodipine on the learnin g ability of rats exposed to electroconvulsive shock were examined. Th e animals were trained in a passive avoidance procedure. The drugs tes ted were injected 30 min before the learning trial started. The electr oconvulsive shock was given immediately after the learning trial respo nse had been acquired. A passive avoidance retention test was performe d 24 h later. It was found that electroconvulsive shock strongly impai red the retention of the passive avoidance response. Nimodipine, felod ipine and amlodipine did not influence the passive avoidance behavior in the sham electroconvulsive shock group, but significantly improved the retention deficits in the animals exposed to electroconvulsive sho ck. These findings support the hypothesis that perturbations in Ca2+ h omeostasis can contribute to the memory deficits associated with elect roconvulsive shock. The antiamnestic effects of the substances tested make them interesting candidates for-clinical trials in patients with cognitive impairment caused by electroconvulsive shock therapy.