Effect of high-salt diet on NO release and superoxide production in rat aorta.
Sprague-Dawley rats were fed either a high-salt (HS) diet (4.0% NaCl) or a low-salt (LS) diet (0.4% NaCl) for 3 days. Nitric oxide (NO) and superoxide production were assessed in the thoracic aorta by evaluating the fluorescence signal intensity from 4,5-diaminofluorescein (DAF-2DA) and dihydroethidine, respectively. Methacholine caused increased NO release in the aortas from rats on a LS but not HS diet. The SOD mimetic tempol restored methacholine-induced NO release in aortas from rats on a HS diet. Methacholine also caused superoxide production in the aortas of rats on a HS diet but not in the aortas of rats on a LS diet. Tempol and N(G)-monomethyl-l-arginine eliminated methacholine-induced superoxide production in the aortas of rats on a HS diet. Aortic rings from rats on the HS diet showed impaired methacholine-induced relaxation, which was improved by tempol. Tempol alone caused a NO-dependent relaxation of norepinephrine-precontracted aortas that was significantly greater in the aortas of rats on the HS diet than in vessels from rats on the LS diet. These data suggest that a HS diet impairs endothelium-dependent relaxation via reduced NO levels and increased superoxide production.
Zhu
Jiaxuan
J
Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Mori
Takefumi
T
Huang
Tianjian
T
Lombard
Julian H
JH
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017673:Sodium Chloride, Dietary / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D017673:Sodium Chloride, Dietary; D016210:Methacholine Chloride; D013481:Superoxides; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D014969:Xanthine Oxidase