Role of ATP-sensitive potassium channels in coronary microvascular autoregulatory responses

T. Komaru, K. G. Lamping, C. L. Eastham, K. C. Dellsperger

Research output: Contribution to journalArticle

103 Scopus citations

Abstract

The purpose of the present study was to test the hypothesis that ATP-sensitive potassium channels mediate autoregulatory vasodilatation of coronary arterioles in vivo. Experiments were performed in 23 open-chest anesthetized dogs. Coronary arterial microvascular diameters were directly measured with fluorescence microangiography using an intravital microscope and stroboscopic epi-illumination synchronized to the cardiac cycle. A mild coronary stenosis (perfusion pressure=60 mm Hg), a critical coronary stenosis (perfusion pressure=40 mm Hg), and complete coronary artery occlusion were produced with an occluder around the left anterior descending coronary artery in the presence or absence of glibenclamide (10-5 M, topically), which inhibits ATP-sensitive potassium channels, or of vehicle. During topical application of vehicle (0.01% dimethyl sulfoxide), there was dilatation of small (<100 μm diameter) arterioles during reductions in perfusion pressure (percent change in diameter: 6.7±1.5%, 11.7±3.5%, and 10.4±5.1% during mild stenosis, critical stenosis, and complete occlusion, respectively). In the presence of glibenclamide, arteriolar dilatations during coronary stenoses and occlusions were abolished. Glibenclamide did not affect responses of arterioles > 100 μm. Glibenclamide did not alter microvascular responses to nitroprusside. These data suggest that ATP-sensitive potassium channels play an important role in determining the coronary microvascular response to reductions in perfusion pressure.

Original languageEnglish (US)
Pages (from-to)1146-1151
Number of pages6
JournalCirculation research
Volume69
Issue number4
DOIs
StatePublished - Jan 1 1991

Keywords

  • Autoregulation
  • Coronary arterioles
  • Glibenclamide
  • Intravital microscopy
  • Ischemia
  • Microcirculation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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