Peroxynitrite-mediated vasorelaxation: Evidence against the formation of circulating S-nitrosothiols

Jonathan E. Graves, Stephen J. Lewis, Neil W. Kooy

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33 Scopus citations


Peroxynitrite-induced relaxation of isolated vessels may involve the formation of S-nitrosothiols. This study characterized the hemodynamic effects of systemically injected peroxynitrite in pentobarbital sodium-anesthetized rats and determined whether these effects were due to the formation of S-nitrosothiols. We utilized L-penicillamine, which attenuates the hemodynamic effects of systemically injected S-nitrosothiols. The hemodynamic effects of peroxynitrite and the S-nitrosothiols L-S-nitrosocysteine, L-S-nitrosoglutathione, and S-nitrosoalbumin were determined before and 25 min after the administration of L-penicillamine or saline. Peroxynitrite and the S-nitrosothiols produced dose-dependent reductions in mean arterial pressure and mesenteric and hindquarter vascular resistances. The hypertensive and vasodilator effects of the S-nitrosothiols were significantly reduced by L-penicillamine. In contrast, the hemodynamic actions of peroxynitrite were unaffected by L-penicillamine. Therefore, peroxynitrite produces hypotensive and vasodilator responses in anesthetized rats that are unlikely to be due to the formation of circulating S-nitrosothiols. The mechanisms by which peroxynitrite produces vasodilatation in vivo remain to be determined.

Original languageEnglish (US)
Pages (from-to)H1001-H1008
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number3 Pt 2
StatePublished - Mar 1998


  • Nitric oxide
  • S- nitrosoalbumin
  • S-nitrosocysteine
  • S-nitrosoglutathione
  • Vasodilatation


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