General and Regional Circulatory Effects of Synthetic Bradykinin in Man.

• Bradykinin is a potent vasodilator in several animal species. The circulatory effects of bradykinin in man have been less extensively studied. Fox et al. observed that intra-arterial or intravenous administration of bradykinin increased blood flow to the hand and forearm. These investigators also found that blood flow to the skin of the hand, forearm, face, and neck increased during the administration of bradykinin. Burch and DePasquale* reported that intra-arterial injection of bradykinin produced digital vascular responses similar to those seen during reactive hyperemia. They concluded that bradykinin selectively closed digital arteriovenous anastomoses. Gersmeyer and Spitzbarth found that single intravenous injections of 50 to 100 fig of bradykinin caused reduction in arterial blood pressure, acceleration of heart rate, increase in cardiac output and stroke volume, and fall in systemic vascular resistance. Comparable doses injected into the superior vena cava or pulmonary artery increased pulmonary arterial pressure. Injections of bradykinin into the femoral artery caused increased blood flow to the calf and rise in skin temperature. Saameli and Eskes •"' reported that intravenous infusions of 0.25 to 0.5 ftg of bradykinin per minute per kilogram body weight lowered arterial blood pressure and accelerated heart rate.