Central physiological effects of experimental intravenous procaine hydrochloride

Abstract

✓ In acute experiments with adult cats, a 5 mg/kg bolus of procaine hydrochloride blocked the reflex vagal slowing elicited by stimulation of the carotid sinus nerve. That this blockade does not represent a generalized depression of central nervous system function is indicated by the fact that the superficial reflexes appeared undiminished when the cardiac response was completely abolished. In unanesthetized, freely-moving cats with chronically-implanted cortical and depth electrodes, the electroencephalogram and behavior were not altered at doses well in excess of those required to abolish the baroreceptor reflex. This central reflex blockade was not altered in animals immobilized with succinylcholine. Procaine hydrochloride was several times more effective than lidocaine in blocking the central reflex response, suggesting a mechanism not directly dependent on anesthetic potency. Interruption of the reflex and its continuing blockade were dose-related.