THE NATURE OF THE ARTERIAL HYPERTENSION PRODUCED IN NORMAL SUBJECTS BY THE ADMINISTRATION OF ANGIOTONIN 1

Abstract

Angiotonin, when given intraven. to normal subjects, produces arterial hypertension with which are associated some of the circulatory manifestations of myocardial failure. These include increased venous pressure, decreased vital capacity, increased heart size, decreased cardiac output (ballistocardiographic) and increased circulation time. There is bradycardia, probably vagal in origin, since it can be prevented by atropine. The electrocardiogram reveals no important changes. The spinal fluid pressure is not significantly altered. The temp.of the skin and blood flow in the limbs tend to decrease, but remain under the control of the sympathetic nervous system. If full, local vasodilatation is produced by 5 minutes'' arterial occlusion, the blood flow increases with the rise of arterial pressure. The pressor response to the cold test of Hines and Brown (immersion of a hand in ice water for 1 min.) is not altered during the hypertension produced by angiotonin. Mild symptoms of dizziness, substernal oppression, headache, nausea or palpitation may be noted. The effects of angiotonin can be maintained at a stable level by regulation of the rate of intraven. infusion, and they subside 4-10 mins. after the cessation of the adm.