THE INFLUENCE OF DIZOCILPINE (MK-801) ON THE RESERPINE-ENHANCED ELECTROMYOGRAPHIC STRETCH REFLEX IN RATS

The electromyographic (EMG) stretch reflex in the gastrocnemius and ti bialis anterior muscles was elicited by passive bending and stretching of the rat's hind foot in the ankle joint. The EMG stretch reflex was increased by pretreatment with reserpine (10 mg/kg ip) which is a mod el compound commonly used to induce parkinsonian rigidity in laborator y animals. Dizocilpine (MK-801) (0.32, 0.64 and 1.28 mg/kg sc) inhibit ed long-latency supraspinal components of the reserpine-increased EMG stretch reflex, whereas a short latency spinal component was not dimin ished. The present results suggest that MK-801 exhibits an antiparkins onian action against reserpine-induced rigidity.