Effects of indomethacin on beta adrenoreceptor-stimulated renin release in the dog

The hypothesis that prostaglandins participate in beta adrenoreceptor-stimulated renin release was tested by examining the effects of prostaglandin synthesis inhibition on renal nerve stimulation (0.5-5.0 Hz)-induced renin release. In phentolamine (5 micrograms/kg/min, intrarenal artery)-treated dogs (n = 6), renal nerve stimulation produced a frequency-related increase in renal renin secretion rate, without altering renal blood flow. In phentolamine plus propranolol (0.3 mg/kg i.v. bolus + 5 micrograms/kg/min infusion)-treated dogs (n = 6), renal nerve stimulation-induced renin release was inhibited by 86% (P less than .03), 75% (P less than .03) and 73% (P less than .02) at 1, 2 and 5 Hz, respectively. In contrast to propranolol, blockade of prostaglandin synthesis with indomethacin (8 mg/kg i.v. bolus) failed to alter the renin secretory response to renal nerve stimulation in phentolamine-treated animals. These results indicate that, in a situation of intrarenal alpha adrenoreceptor blockade, renal nerve stimulation induces renin secretion by a beta adrenoreceptor mechanism that is independent of prostaglandin biosynthesis.