title: Myocardial and endothelial dysfunction after multiple, brief coronary occlusions: role of oxygen radicals.
abstract: The major objective of the present study was to determine the effect of multiple, brief periods of coronary artery occlusion and reperfusion on postischemic contractile function (sonomicrometry) and endothelium-dependent vasodilator responses in isolated conduit coronary artery rings obtained from anesthetized dogs. The role of oxygen-derived free radicals was also investigated. Dogs were subjected to four 5-min episodes of left anterior descending coronary occlusion interspersed with 5 min of reperfusion followed by a final 60-min reperfusion period. The multiple occlusion-reperfusion protocol resulted in regional segment dysfunction (37 +/- 15% of preocclusion values at 60 min of reperfusion) and attenuated endothelium-dependent responses to acetylcholine, bradykinin, and the calcium ionophore, A23187. Responses to the endothelium-independent vasodilator, sodium nitroprusside, were unaffected. Infusion of superoxide dismutase (5,000 U/kg) and catalase (55,000 U/kg) markedly improved the recovery of myocardial function at 30 and 60 min of reperfusion and completely protected against vascular endothelial damage. These results suggest an important role for oxygen-derived free radicals in the myocardial and endothelial injury that occurs in this model of multiple stunned myocardium.
authors: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
authors: G J
authors: GJ
authors: Gross
authors: S T
authors: ST
authors: O'Rourke
authors: L R
authors: LR
authors: Pelc
authors: D C
authors: DC
authors: Warltier
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics; D008297:Male; D009200:Myocardial Contraction; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012008:Recurrence; D012307:Risk Factors
chemical_list: D017382:Reactive Oxygen Species