Modulation of reflex renal vasoconstriction by increased endogenous renal prostaglandin synthesis.

The effect of increased endogenous renal prostaglandin synthesis on the reflex renal vasoconstrictor response to stimulation of skeletal muscle somatic receptors and their afferents was examined in anesthetized dogs with bilateral carotid artery occlusion and vagotomy. Acute ureteral occlusion and indomethacin were used to acutely increase and decrease, respectively, endogenous renal prostaglandin synthesis. Graded electrical stimulation of the afferent sciatic nerve or antegrade femoral arterial injection of capsaicin elicited a frequency dependent reduction in renal blood flow accompanied by increases in mean arterial pressure and heart rate. Acute ureteral occlusion attenuated (circa 50%) the renal vasoconstrictor response but did not affect the increases in mean arterial pressure or heart rate. Administration of indomethacin during continued ureteral occlusion restored the renal vasoconstrictor responses to the preureteral occlusion level. These results indicate that the increase in endogenous renal prostaglandin synthesis during acute ureteral occlusion specifically attenuates the reflex renal vasoconstrictor response to stimulation of skeletal muscle somatic receptors and their afferents.