Reactive oxygen species mediate arachidonic acid-induced dilation in porcine coronary microvessels.

Journal Article (Journal Article)

Reactive oxygen species (ROS) have been proposed to mediate vasodilation in the microcirculation. We investigated the role of ROS in arachidonic acid (AA)-induced coronary microvascular dilation. Porcine epicardial coronary arterioles (110 +/- 4 microm diameter) were mounted onto pipettes in oxygenated Krebs buffer. Vessels were incubated with vehicle or 1 mM Tiron (a nonselective ROS scavenger), 250 U/ml polyethylene-glycolated (PEG)-superoxide dismutase (SOD; an O2- scavenger), 250 U/ml PEG-catalase (a H2O2 scavenger), or the cyclooxygenase (COX) inhibitors indomethacin (10 microM) or diclofenac (10 microM) for 30 min. After endothelin constriction (30-60% of resting diameter), cumulative concentrations of AA (10(-10)-10(-5)M) were added and internal diameters measured by video microscopy. AA (10-7 M) produced 37 +/- 6% dilation, which was eliminated by the administration of indomethacin (4 +/- 7%, P < 0.05) or diclofenac (-8 +/- 8%, P < 0.05), as well as by Tiron (-4 +/- 5%, P < 0.05), PEG-SOD (-10 +/- 6%, P < 0.05), or PEG-catalase (1 +/- 4%, P < 0.05). Incubation of small coronary arteries with [3H]AA resulted in the formation of prostaglandins, which was blocked by indomethacin. In separate studies in microvessels, AA induced concentration-dependent increases in fluorescence of the oxidant-sensitive probe dichlorodihydrofluorescein diacetate, which was inhibited by pretreatment with indomethacin or by SOD + catalase. We conclude that in porcine coronary microvessels, COX-derived ROS contribute to AA-induced vasodilation.

Full Text

Duke Authors

Cited Authors

  • Oltman, CL; Kane, NL; Miller, FJ; Spector, AA; Weintraub, NL; Dellsperger, KC

Published Date

  • December 2003

Published In

Volume / Issue

  • 285 / 6

Start / End Page

  • H2309 - H2315

PubMed ID

  • 12869369

International Standard Serial Number (ISSN)

  • 0363-6135

Digital Object Identifier (DOI)

  • 10.1152/ajpheart.00456.2003


  • eng

Conference Location

  • United States