Beneficial effect of ischemic preconditioning on Ca2+ paradox in the rat heart.
The effect of ischemic preconditioning (IP; 3 min ischemia plus 3 min reperfusion) on the recovery of cardiac function after Ca2+ depletion was investigated. Isolated rat hearts were subjected to different cycles of IP episodes followed by Ca2+ free perfusion and repletion. Perfusion of control hearts with Ca2+ free medium for 5 min followed by repletion of Ca2+ for 30 min resulted in a marked decrease in the left ventricular (LV) developed pressure and an increase in LV end-diastolic pressure (Ca2+ paradox). The depressed function due to Ca2+ paradox recovered with three cycles of IP. Myoglobin release during Ca2+ repletion also decreased significantly by three cycles of IP. The beneficial effects of IP were also evident when the hearts were subjected to a mild form of Ca2+ paradox involving 3 min Ca2+ depletion. The protective effect rendered by IP disappeared when 10 microM of 8-(p-sulfophenyl)-theophylline, adenosine antagonist was perfused for 10 min before IP. These results suggest that IP exerts beneficial effects on Ca2+ paradox which may be mediated by adenosine.
St. Boniface General Hospital Research Centre and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
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Kawabata
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M
Osada
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Netticadan
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Dhalla
D000818:Animals; D001794:Blood Pressure; D002118:Calcium / Q000378:metabolism*; D003971:Diastole; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009211:Myoglobin / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016277:Ventricular Function, Left
D009211:Myoglobin; D002118:Calcium