The effects of propanidid on arterial pressure, pulse rate, preganglionic sympathetic activity and barostatic reflexes in the cat.

We have studied the effects of propanidid on preganglionic cervical sympathetic nervous activity, arterial pressure, pulse rate and barostatic reflexes of the cat. Normal, hypertensive, baroreceptor denervated and decerebrate animals with sectioned vagal nerves were studied. On the basis of our findings it is concluded that propanidid exerts its depressant action on the cardiovascular system directly. Central circulatory control mechanisms are essentially unaffected. The depression of arterial pressure caused by propanidid is moderated by two compensatory mechanisms: normal barostatic reflexes causing an increased sympathetic tone in response to hypotension and a vagolytic action of propanidid.