Depression of reserpine-induced muscular rigidity in rats after administration of lisuride into the spinal subarachnoid space.

Muscular rigidity was induced by reserpine (10 mg/kg) in rats and the tonic activity of the gastrocnemius muscle was recorded in the electromyogram. Systemic administration of lisuride, an ergoline, resulted in a dose-dependent depression of rigidity. To examine the spinal cord as a site of action for lisuride to depress reserpine-induced rigidity, a method for the chronic catheterization of the lumbar spinal subarachnoid space was used, which allowed the administration of drugs to reserpinized, intact rats without anaesthesia. Lisuride injected into the lumbar spinal subarachnoid space resulted in a longlasting depression of rigidity. These results suggest that the spinal cord is an important site of action of lisuride.