title: Interaction between nitric oxide and renal myogenic autoregulation in normotensive and hypertensive rats.
abstract: Blood pressure fluctuates continuously throughout life and autoregulation is the primary mechanism that isolates the kidney from this fluctuation. Compared with Wistar rats, Brown Norway (B-N) rats display impaired renal myogenic autoregulation when blood pressure fluctuation is increased. They also are very susceptible to hypertension-induced renal injury. Because blockade of nitric oxide augments myogenic autoregulation in Wistar rats, we compared the response of the myogenic system in B-N rats to nitric oxide blockade with that of other strains [Wistar, Sprague-Dawley, Long-Evans, spontaneously hypertensive (SHR)]. Renal blood flow dynamics were assessed in isoflurane anesthetized rats before and after inhibition of nitric oxide synthase by Lomega-nitro-arginine methyl-ester (L-NAME, 10 mg/kg, iv). Under control conditions, myogenic autoregulation in the B-N rats was weaker than in the other strains. Myogenic autoregulation was not augmented after L-NAME administration in the SHR, but was augmented in all the normotensive rats. The enhancement was significantly greater in B-N rats so that after L-NAME the efficiency of autoregulation did not differ among the strains. The data suggest that nitric oxide is involved in the impaired myogenic autoregulation seen in B-N rats. Furthermore, the similarity of response in Wistar, Long-Evans, and Sprague-Dawley rats suggests that modulation by nitric oxide is a fundamental property of renal myogenic autoregulation.
authors: Lady Davis Institute, Sir Mortimer B. Davis-Jewish General Hospital, Montréal, Quebec, Canada.
authors: X
authors: X
authors: Wang
authors: W A
authors: WA
authors: Cupples
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology*; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D011914:Rats, Inbred BN; D011918:Rats, Inbred SHR; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester