Central vasomotor effects of a new ganglion-blocking agent--1: 2: 2: 6: 6-pentamethyl piperidine (pempidine).

The central vasomotor effects of pempidine were studied in dogs and cats anaesthetized with pentobarbitone sodium, and in spinal cats. Pempidine lowered the threshold of electrical stimulation of the medulla oblongata to evoke a pressor response when given intravenously to cats in a dose insufficient to block autonomic ganglia. Injection of a small dose into the cerebral ventricles of dogs produced an increase in the pressor responses to occlusion of the carotid artery and to electrical stimulation of the central end of the cut vagus. In the spinal cat small doses of pempidine, given either intravenously or intrathecally, augmented the rise in blood pressure resulting from compression of the spinal cord. Since all these effects were produced by pempidine in doses insufficient to cause ganglionic block, the observed effects are attributed to central facilitation of the vasomotor responses. Thus pempidine has a stimulant action on the spinal and supraspinal centres.