Abstract
The effects of chlorpromazine, promazine, diethazine, reserpine, hydroxyzine and morphine on some mono- and polysynaptic motor reflexes have been investigated in intact, spinal and decerebrate cats and rabbits. Chlorpromazine, promazine, reserpine and hydroxyzine selectively depress the monosynaptic spinal reflexes (knee jerk) of the intact animals. Polysynaptic reflexes (linguo-mandibular and crossed extensor) are slightly affected. In both cats and rabbits the brain of which was disconnected from the spinal cord by surgical sections at different levels, the inhibitory action of these drugs disappears. Morphine and diethazine, on the contrary, selectively depress the polysynaptic reflexes (linguo-mandibular) and in a minor degree the monosynaptic ones (knee jerk): this action is retained in spinal animals. These findings are discussed and related to other pharmacological properties of the compounds.