Hypertensive Effects of Bradykinin in Rats

Abstract

BRADYKININ obtained from ox plasma¹ and synthetic bradykinin cause intense vasodilatation in many mammalian species. Intravenous injections of bradykinin lower arterial blood pressure in anæsthetized animals. On a molar basis, bradykinin is only ten times less active than acetylcholine and as active as histamine¹. Two crude bradykinin-containing extracts from ox plasma—one prepared by us and the other kindly supplied by Prof. Rocha e Silva—were shown to have the typical depressor action in normal rats, but frequently produced a striking hypertensive effect in rats nephrectomized 16–24 hr. before. These results are similar to those obtained with anephrotensin prepared from rat serum².