Bradykinin B-2 receptor antagonism attenuates blood pressure response to acute angiotensin-converting enzyme inhibition in normal men

The physiological effects of angiotensin-converting enzyme (ACE) inhibition may be in part mediated by bradykinin. We investigated the effect of coadm inistration of the specific bradykinin B-2 receptor antagonist icatibant on hemodynamic and neurohormonal responses to acute intravenous ACE inhibitio n in normal men on a normal sodium diet. We performed a 4-phase, double-bli nd, double-dummy, placebo-controlled study in 12 male volunteers. The brady kinin antagonist icatibant (10 mg IV) was coadministered over the first 15 minutes of a 2-hour infusion of the ACE inhibitor perindoprilat (1.5 mg IV) . Perindoprilat inhibited ACE activity and elicited the expected changes in active renin concentration and angiotensin peptides. Over the 3 hours afte r the start of drug infusion, perindoprilat lowered and icatibant increased mean arterial blood pressure (each P<0.0005 versus placebo). Coadministrat ion of icatibant attenuated the mean arterial blood pressure response to pe rindoprilat (P<0.0005) but had no effect on neurohormonal responses to peri ndoprilat. Our study indicates that the bradykinin B-2 receptor antagonist icatibant attenuates the short-term blood pressure-lowering effect of acute ACE inhibition in normal men on a normal sodium diet. Bradykinin B-2 recep tor antagonism alone increases resting blood pressure. Bradykinin may be in volved in the control of blood pressure in the resting state in humans.