[The effect of isradipine on the morphine-activated self-stimulation reaction in rats]

Lateral hypothalamic self-stimulation in rats was studied using two schedules of reinforcement: continuous reinforcement and fixed-ratio schedule. Isradipine, the blocker of calcium channels (1, 2, 4 mg/kg, subcutaneously) dose-dependently decreased self-stimulation rate and increased the threshold intensity in continuous reinforcement schedule, as well as suppressed self-stimulation under fixed-ratio schedule. The data obtained count in favour of common dihydropyridine-sensitive mechanism of the reinforcing effect of both electrical and pharmacological activation of the brain reward system.