Decreased spontaneous motor activity parallels reserpine-induced supersensitivity of catecholamine-responsive rat cerebral cortex adenylate cyclase

Spontaneous motor activity and catecholamine responsiveness of brain adenylate cyclases were measured in albino rats after 4 days of reserpine injections (0.25 mg/kg/day, subcutaneous). Motor activity was significantly decreased in reserpine-treated rats in the 24-hr period following the final reserpine injection. Responses of cerebral cortex adenylate cyclase to norepinephrine (1–100 μM) and dopamine (10–100 μM) were increased during this same period. Catecholamine responses of striatal adenylate cyclase were not significantly increased by reserpine treatment. These results support prior suggestions that the cerebral cortex adenylate cyclase system may have an inhibitory function with respect to spontaneous motor behavior in the rat.