Nitric oxide influences blood flow distribution in renovascular hypertension.
Endothelium-derived nitric oxide contributes to the regulation of regional blood flow. Inhibition of endothelium-derived nitric oxide synthesis increases blood pressure and vascular resistance. Using the substrate antagonist N omega-nitro-L-arginine-methyl ester to block endothelium-derived nitric oxide synthesis, we tested the hypothesis that, in two-kidney, one clip renovascular hypertension, endothelium-derived nitric oxide plays an increased role in maintaining blood flow to the nonclipped kidney and other visceral organs compared with normotensive controls. This could be due to increased vascular shear stress, a primary stimulus for endothelium-derived nitric oxide synthesis, after the onset of hypertension. In hypertensive rats with mild renal artery stenosis, basal renal blood flow normalized by kidney weight was similar in the nonclipped and clipped kidneys. Basal blood pressure of controls was 98 +/- 2 mm Hg compared with 145 +/- 3 mm Hg in the two-kidney, one clip hypertensive rats. N omega-nitro-L-arginine-methyl ester increased blood pressure by 20 +/- 2 and 43 +/- 3 mm Hg in control and hypertensive rats, respectively. Compared with normotensive controls, basal resistance was higher in all organ beds in the hypertensive rats including brain, heart, intestine, and kidney. With the exception of the renal circulation, the increase in vascular resistance after N omega-nitro-L-arginine-methyl ester was greater in hypertensive rats compared with normotensive controls. In the hypertensive rats, N omega-nitro-L-arginine-methyl ester caused a similar increase in vascular resistance in both the nonclipped and clipped kidneys, and this was not different from normotensive controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Sigmon
D H
DH
Hypertension and Vascular Research Division, Ford Hospital, Detroit, MI 48202-2689.
Beierwaltes
W H
WH
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000098:blood supply; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D002565:Cerium Radioisotopes; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006614:Hindlimb / Q000098:blood supply; D006978:Hypertension, Renovascular / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply; D008297:Male; D008863:Microspheres; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology*; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology; D013324:Strontium; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D002565:Cerium Radioisotopes; D009569:Nitric Oxide; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester; D013324:Strontium