Effects of an antihypertensive drug, pentolinium

Abstract

The action of pentolinium and of eight pressor agents, alone and in combination, on the blood pressure and pulse rate of normal, unanesthetized dogs was investigated. The slow, continuous infusion of the ganglionic blocking agent induced reactions considerably different from those of other investigators who administered single massive doses to animals subjected to anesthesia or to various surgical procedures. To elucidate the mechanism of the well known potentiation of pressor agents by ganglionic blocking agents, the effects were investigated of simultaneous ganglionic and adrenergic blockade, of acetylcholine and atropine and of nicotine and other ganglionic stimulating agents. The results of some of these experiments are at variance with previous concepts, and it appears that the potentiation phenomenon can be ascribed neither to a release of sympathomimetic amines nor to a blockade of compensatory, autonomic buffer reflexes by pentolinium. An alternate explanation is that pentolinium may be competing with the continuous ‘background’ dilating action of intrinsically liberated acetylcholine in the wall of the arterioles, thus inducing an increased responsiveness of these vessels to vasoconstriction.