Renin release in rats during blockade of nitric oxide synthesis.
The influence of renal perfusion pressure on renin release was examined in rats administered the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). Compared with the control plasma renin of 6.0 +/- 0.7 ng angiotensin I (ANG I).ml-1.h-1, plasma renin activity was suppressed (1.8 +/- 0.2 ng ANG I.ml-1.h-1, P < 0.05) in L-NAME-treated animals in which the renal perfusion pressure was permitted to increase and reached 141 +/- 8 mmHg. Plasma renin activity also was suppressed (2.5 +/- 0.4 ng ANG I.ml-1.h-1, P < 0.05) in a second L-NAME-treated group in which the renal perfusion pressure was controlled to a level of 105 +/- 5 mmHg via tightening of a suprarenal aortic snare. Plasma renin activity was increased (12.0 +/- 1.4 ng ANG I.ml-1.h-1, P < 0.05) in a third L-NAME-treated group in which renal perfusion pressure was reduced to 59 +/- 1 mmHg. Overall, these findings suggest that the intrarenal pressure-sensing mechanism for renin release does not stringently require nitric oxide synthesis. In a second experimental series, bilaterally renal-denervated rats were administered L-NAME, and again plasma renin activity was suppressed significantly whether renal perfusion pressure was permitted to increase or was controlled. Thus L-NAME also suppressed plasma renin activity independently of reflex reductions in renal neuroadrenergic activity even when renal perfusion pressure was controlled. Infusions of sodium nitroprusside completely inhibited L-NAME-induced suppression of plasma renin activity in these renal-denervated rats. Nitric oxide may function as a paracrine stimulatory mechanism for the local regulation of renin release.
Department of Physiology, University of Missouri School of Medicine, Columbia 65212.
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Johnson
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Freeman
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003714:Denervation; D007668:Kidney / Q000294:innervation; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D009599:Nitroprusside / Q000494:pharmacology; D010477:Perfusion; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation; D012083:Renin / Q000097:blood*
D009599:Nitroprusside; D009569:Nitric Oxide; D001120:Arginine; D012083:Renin; D019331:NG-Nitroarginine Methyl Ester