Control of canine renin release: macula densa requires prostaglandin synthesis.

Abstract

The macula densa mechanism of renin release was functionally isolated in uninephrectomized, anesthetized dogs by producing renal denervation, .beta.-adrenoceptor blockade and maximum renal vasodilation with an infusion of papaverine into the renal artery. A suprarenal aortic clamp was adjusted to reduce renal perfusion pressure by 50% which resulted in a 90% reduction in urinary Na excretion and a 2- to 3-fold increase in plasma renin activity within 10 min. Indomethacin (8 mg/kg) or meclofenamic acid (10 mg/kg) inhibited the rise in plasma renin activity produced by the decrease in renal perfusion pressure in this model, although a comparable decrease in urinary Na excretion was achieved. The macula densa mechanism of renin release apparently is blocked by inhibition of prostaglandin synthesis.