Mechanism of superoxide anion-induced modulation of vascular tone

Lalita A. Bharadwaj; Kailash Prasad

doi:10.1007/s00547-001-0049-5

International Journal of Angiology, Table of Contents

Int J Angiol 2002; 11(1): 23-29
DOI: 10.1007/s00547-001-0049-5

Original Articles

Mechanism of superoxide anion-induced modulation of vascular tone

Lalita A. Bharadwaj, Kailash Prasad

Toxicology Group and Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Abstract

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Abstract

We investigated the effects of superoxide anions (O₂−) generated by xanthine (X) plus xanthine oxidase (XO) on isolated rabbit aorta suspended in Krebs-Ringer solution. Xanthine plus xanthine oxidase produced concentration-dependent contractions of rabbit aorta. Superoxide dismutase completely reversed the contractile response observed. Superoxide anion-induced contraction of rabbit aorta was totally abolished in preparations denuded of endothelium. The contractile effect was reduced by 56% by the cyclooxygenase inhibitor, indomethacin. The contractile effect was not affected by the angiotensin converting enzyme inhibitor, captopril. These results indicate that O₂ ⁻ produces a contraction of the isolated rabbit aorta that is endothelium-dependent and is partly mediated by an arachidonic acid metabolite.

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