Hyperoxic Vasoconstriction in the Brain Is Mediated by Inactivation of Nitric Oxide by Superoxide Anions

S. Yu Zhilyaev, A. N. Moskvin, T. F. Platonova, D. R. Gutsaeva, I. V. Churilina, I. T. Demchenko

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

The hypothesis that decreases in brain blood flow during respiration of hyperbaric oxygen result from inactivation of nitric oxide (NO) by superoxide anions (O2-) is proposed. Changes in brain blood flow were assessed in conscious rats during respiration of atmospheric air or oxygen at a pressure of 4 atm after dismutation of O2- with superoxide dismutase or suppression of NO synthesis with the NO synthase inhibitor L-NAME. I.v. administration of superoxide dismutase increased brain blood flow in rats breathing air but was ineffective after previous inhibition of NO synthase. Hyperbaric oxygenation at 4 atm induced decreases in brain blood flow, though prior superoxide dismutase prevented hyperoxic vasoconstriction and increased brain blood flow in rats breathing hyperbaric oxygen. The vasodilatory effect of superoxide dismutase in hyperbaric oxygenation was not seen in animals given prior doses of the NO synthase inhibitor. These results provide evidence that one mechanism for hyperoxic vasoconstriction in the brain consists of inactivation of NO by superoxide anions, decreasing its basal vasorelaxing action.

Original languageEnglish (US)
Pages (from-to)783-787
Number of pages5
JournalNeuroscience and Behavioral Physiology
Volume33
Issue number8
DOIs
StatePublished - Oct 1 2003
Externally publishedYes

Keywords

  • Brain blood flow
  • Hyperbaric oxygenation
  • Nitric oxide
  • Superoxide anion
  • Superoxide dismutase

ASJC Scopus subject areas

  • Neuroscience(all)

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