INFLUENCE OF ISRADIPINE ON MORPHINE-ACTIV ATED SELF-STIMULATION IN RATS

Lateral hypothalamic self-stimulation in rats was studied using two sc hedules of reinforcement: continuous reinforcement and fixed-ratio sch edule. Isradipine, the blocker of calcium channels (1, 2, 4 mg/kg, sub cutaneously) dose-dependently decreased self-stimulation rate and incr eased the threshold intensity in continuous reinforcement schedule, as well as suppressed self-stimulation under fixed-ratio schedule. The d ata obtained count in favour of common dihydropyridine-sensitive mecha nism of the reinforcing effect of both electrical and pharmacological activation of the brain reward system.