Salt-sensitive hypertension in bradykinin B-2 receptor knockout mice

The kallikrein-kinin system regulates water and sodium excretion and thus plays a role in blood pressure (BP) homeostasis. We tested the hypothesis that mice lacking the gene encoding for the bradykinin B-2 receptor (B-2-KO) have a greater hypertensive response to chronic high Na+ intake (salt sensitivity) compared to controls. We also obtained dose-response curves for different vasoactive substances in both groups. The hypertensive effect of high Na+ intake was almost doubled in B-2-KO mice compared to controls. A high-Na+ diet increased heart and kidney weight in B-2-KO, but not in controls, suggesting an increased afterload in B-2-KO mice. The BP response to bradykinin was completely abolished in B-2-KO, but that to acetylcholine was conserved. The hypertensive response to angiotensin II was nor exaggerated in B-2-KO mice. This study describes a new salt-sensitive animal model and suggests that in mice kinins play a role in preventing salt-sensitive hypertension. (C) 1996 Academic Press, Inc.