Adrenal-dependent circulatory responses to angiotensin in the cat

Abstract

Blood flow changes in the femoral arteries of anesthetized cats following intravenous angiotensin were studied by means of gated sine-wave electromagnetic flowmeters and noncannu-lating probes. After a delay of 20-40 sec. angiotensin produced a vasodilatation in the skeletal muscle of both innervated and denervated limbs and a transient reduction of the angiotensin pressor response. The late dilator response was abolished by beta adrenergic blockade. Adrenal ligation also abolished the dilator response but in these animals the intravenous injection of epinephrine 10-20 sec. after the administration of angiotensin duplicated the response produced by angiotensin alone before adrenal ligation. It was concluded that angiotensin releases epinephrine from the adrenal medulla with a consequent increase in blood flow to skeletal muscle.