Different responses of renal blood flow and sympathetic nerve activity to captopril and nicardipine in conscious renal hypertensive rabbits

To elucidate the roles of endogenous angiotensin II (AII) and renal sympathetic nerve activity (RSNA) in modulation of renal blood flow (RBF), we recorded RBF and RSNA in conscious two-kidney, one-clip (2KIC) hypertensive rabbits with blood pressure (BP) reduced to a similar extent by captopril (5 mg/kg) and nicardipine (4.3 μg/kg/min). We measured plasma concentrations of AII, arginine vasopressin (AVP), and norepinephrine (NE). Despite comparable depressor effects, changes in RBF showed different profiles with the two drugs in renal hypertensive rabbits. After captopril injection, RBF was consistently increased to 143±7%