Effect of superoxide dismutase and catalase on regional dysfunction after exercise-induced ischemia.
This study was designed to test the hypothesis that the oxygen free radical scavengers superoxide dismutase (SOD) and catalase may reduce myocardial "stunning" after exercise-induced ischemia. To test this hypothesis, 8 mongrel dogs performed treadmill exercise for 10 min in the presence of a flow-limiting coronary artery stenosis. Regional left ventricular function was measured with ultrasonic microcrystals implanted to measure regional wall thickening. Regional myocardial perfusion was measured with radioactive microspheres. The combination of SOD (5 mg/kg iv) and catalase (5 mg/kg iv) did not affect heart rate, blood pressure, coronary artery flow, or regional myocardial blood flow at rest, during exercise, or in the postexercise period. SOD and catalase had no effect on regional wall thickening at rest before exercise. During exercise in the absence of a coronary artery stenosis, thickening was slightly lower during SOD and catalase infusion (27 +/- 11.0 vs. 30.8 +/- 11.5%, SOD vs. control P = 0.05). During exercise in the presence of a coronary artery stenosis, there was no difference in thickening. Infusion of SOD and catalase affected neither the transient rebound function occurring early after exercise nor the prolonged period of stunning. These results indicate that the myocardial stunning that follows exercise-induced ischemia is unlikely to be mediated by oxygen free radicals.
Homans
D C
DC
Department of Medicine, University of Minnesota Medical School, Minneapolis 55405.
Asinger
R
R
Pavek
T
T
Crampton
M
M
Lindstrom
P
P
Peterson
D
D
Bache
R J
RJ
D000818:Animals; D002374:Catalase / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D005082:Physical Exertion; D013482:Superoxide Dismutase / Q000494:pharmacology*; D013599:Systole
D002374:Catalase; D013482:Superoxide Dismutase