Effect of bradykinin on renal function in dogs treated with indomethacin or propranolol

The effect of bradykinin (BK) on renal function was examined in anesthetized dogs with or without treatment with either indomethacin or propranolol. Renal arterial infusion of BK (3 micrograms/min) in control dogs produced a sustained increase in urine flow rate (V), sodium excretion (UNaV), potassium excretion (UKV), and renal plasma flow (RPF) without a consistent change in glomerular filtration rate (GFR) or renin secretion rate (RSR). This increase in salt and water excretion and in RPF could not be blocked with indomethacin (5 mg/kg, followed by 2.1-3.2 mg/kg/h, i.v.). UNaV was 20.8 +/- 7.4 and 123.3 +/- 22.3 muEq/min (mean +/- SEM values) before and after 140 min of infusion of BK (p less than 0.005), respectively. Beta-receptor blockade with propranolol (5 mg/kg, followed by 2.8-3.4 mg/kg/h, i.v.) did not prevent the BK-induced rise in salt and water excretion, or in RPF. UNaV was 26.0 +/- 9.7 and 96.4 +/- 21.5 muEq/min before and after 140 min of infusion of BK (p less than 0.005), respectively. The data suggest that the effects of BK on renal handling of salt and water and on RPF are not mediated by either prostaglandins or beta receptors.