ROLE OF BRADYKININ IN CHRONIC ANTIHYPERTENSIVE ACTIONS OF RAMIPRIL IN DIFFERENT HYPERTENSION MODELS

We investigated the chronic effect of bradykinin B2-receptor blockade on the antihypertensive actions of the angiotensin-converting enzyme (ACE) inhibitor ramipril in three different hypertensive rat models, the two-kidney/one-clip (2K1C) hypertensive Wistar rat, the kinin-deficient 2K1C hypertensive Brown Norway Katholieke (BN-K) rat, and the spontaneously hypertensive rat (SHR). Chronic blockade of bradykinin B2 receptors by subcutaneous infusion of the new bradykinin antagonist HOE 140 (500 mug/kg/day) attenuated the antihypertensive effect of ramipril only in 2K1C hypertensive Wistar rats, but not in 2K1C BN-K rats and SHR. Our data demonstrate for the first time that potentiation of endogenous kinins contributes to chronic antihypertensive actions of ACE inhibitors in experimental renal hypertension. Whether this holds also true for other forms of hypertension remains to be answered.