General and Regional Circulatory Effects of Synthetic Bradykinin in Man

Abstract

The general and regional circulatory effects of synthetic bradykinin were investigated in 19 healthy volunteers. During intravenous infusion of bradykinin (25 µg/min) mean arterial pressure decreased initially, but returned to control levels within a few minutes. Heart rate increased during the hypotensive period, but subsequently returned toward preinfusion levels. Cardiac output increased, mainly as a result of increased stroke volume, and systemic vascular resistance decreased. Blood flow to hand increased during such infusions of bradykinin, but blood flow to forearm was not altered significantly. Intravenous infusions of 40 µg/min produced an increase in blood flow to the forearm, resulting solely from cutaneous vasodilatation in most subjects. The distensibility of hand veins increased both during intravenous infusions of 25 µg/min and during infusions of 0.2 µg/min into the brachial artery. Renal clearance of inulin was slightly decreased during infusion of 25 µg/ min bradykinin; there was no detectable change of PAH clearance.