Studies on the action and interaction of dopamine and prostaglandin A1 in the renal vasculature.

: Dopamine (3 mug/kg/min) and prostaglandin A1 (0.2 mug/kg/min) were found to dilate the renal vasculature and increase total kidney blood flow in be anesthetized dog. These effects of dopamine, but not of prostaglandin A1, were completely antagonized by bulbocapnine, a selective dopamine receptor inhibitor, at a dose (3 mg/kg) which did not itself significantly alter cardiovascular hemodynamics. Conversely, indomethacin, an inhibitor of prostaglandin synthetase in the dog at 2 mg/kg, did not reduce the dopamin renal vascular response. These results suggest that dopamine and PGA1 decrease renal vascular resistance in the dog via distinct pharmacological mechanisms.