Cardiac effects of angiotensin injections into perfused right coronary artery

Abstract

Rapid injections of angiotensin into the right coronary artery caused brief cardiac acceleration prior to cardiac slowing. In ganglion-blocked dogs, intracoronary injections of angio-tensin caused cardiac acceleration on the average 2.3 sec. after in-jection. This is similar to the latent period required for norepinephrine to produce acceleration upon intracoronary injection. In many in-stances the cardioaccelerator response was biphasic. The latent periods for angiotensin to elicit acceleration are significantly longer when angiotensin is injected into the left femoral vein or the left ventricle. The data suggest that intracoronary angiotensin also caused a posi-tive inotropic effect. These observations indicate that angiotensin acts within the heart of ganglioplegic dogs to cause cardiac acceleration. This is probably caused by release of transmitter from adrenergic nerve endings.