The effects of AE0047, a newly developed calcium channel blocker, on renal haemodynamics and function were investigated and compared with those of nicardipine in anaesthetized dogs. 2. Intravenous injection of AE0047 (10 and 30 micrograms/kg) caused a dose-related fall in blood pressure (BP). The AE0047-induced fall in BP was of slow onset and long lasting. AE0047 at 10 micrograms/kg elicited a slight increase in renal blood flow (RBF) and urine formation. 3. When AE0047 was infused intrarenally at non-hypotensive doses (25 and 50 ng/kg per min), there was no significant increase in RBF. However, the glomerular filtration rate increased significantly after drug infusion. Intrarenal arterial (i.r.a.) infusion of AE0047 led to dose-related increases in urine flow (UF), urinary excretion of electrolytes (Na+, K+ and Cl-) and fractional excretion of electrolytes. The AE0047-induced increase in urine formation was of very slow onset and progressed even after the cessation of the AE0047 infusion. 4. The intrarenal arterial infusion of nicardipine at same doses as AE0047 produced significant increases in urine formation, but these effects were immediately restored to the control values after cessation of the nicardipine infusion. 5. It was shown that AE0047 has a long-lasting diuretic effect and that AE0047-induced diuresis may be due to inhibitory effects on sodium and water reabsorption in the renal tubules.
