Vasodilating effect of benidipine hydrochloride in the renal and hindquarter vascular regions (supplied by terminal aorta) of spontaneously hypertensive rats

One of two Ca antagonists, benidipine (3-30 mu g/kg) or nifedipine (30-600 g/kg), was administered in a bolus injection through the jugular vein, and the changes in mean arterial pressure (MAP), renal flow (RF), and hindquart er flow (HQF) in conscious spontaneously hypertensive rats (SHRs) and normo tensive control rats (NCRs). Renal vascular resistance (RR) and hindquarter resistance (HQR) were calculated as MAP divided by RF and HQF, respectivel y. When a high dose was administered to decrease the blood pressure by abou t 20%, the RR was significantly lower with benidipine than with nifedipine. The decrease in HQR was not significantly different between benidipine and nifedipine. When a low dose was administered to decrease the blood pressur e by about 7%, the decrease in RR was not significantly different between b enidipine and nifedipine, but the HQR was significantly lower with benidipi ne than with nifedipine. In the NCRs, no pharmacological properties were si gnificantly different between these two Ca antagonists. (C) 1999 Elsevier S cience Inc. All rights reserved.