Renal effects of acute amino acid infusion in hypertension induced by chronic nitric oxide blockade.
L-Arginine is the physiological substrate of nitric oxide, a vasodilator that controls blood pressure and renal hemodynamics in the basal state. In the present studies, we produced chronic nitric oxide blockade by oral administration of the L-arginine analogue NG-nitro-L-arginine methyl ester, which produced sustained hypertension and increased renal vascular resistance in conscious rats. Acute excess L-arginine had little effect on blood pressure but completely normalized renal vascular resistance and increased renal plasma flow in chronically nitric oxide-blocked hypertensive rats. In contrast to L-arginine, D-arginine had no renal hemodynamic effects in either normal or chronically nitric oxide-blocked rats. Acutely administered glycine was ineffective in vasodilating the chronically nitric oxide-blocked rat kidney, in a dose that produced renal vasodilation in normal rats. These findings indicate the following: (1) Hypertension induced by chronic nitric oxide blockade due to substituted L-arginine analogue cannot be acutely reversed with excess L-arginine, suggesting that the maintenance of the hypertension is not solely caused by competitive inhibition of nitric oxide production; (2) in contrast, the kidney remains responsive to L-arginine whereas the renal vasodilator response to glycine is abolished in this model of hypertension.
Department of Physiology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown 26506-9229.
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Qiu
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Engels
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Samsell
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Baylis
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005998:Glycine / Q000494:pharmacology*; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects
D009569:Nitric Oxide; D001120:Arginine; D005998:Glycine; D019331:NG-Nitroarginine Methyl Ester