ROLE OF Na~+-Ca~(2+) EXCHANGE SYSTEM IN THE PATHOGENESIS OF MYOCARDIAL ISCHEMIA-REPERFUSION DAMAGE

Results from a systematic experiment on isolated perfused rat heart and isolated myc- cytes of adult rat showed that the mechanism of calcium influx during myocardial ischemia- reperfusion is due to the development of intracellular sodium overload during ischemic pe- riod, on reperfusion, the high intracellular Na~+ content activated the reverse direction of Na~+-Ca~(2+) exchange over myocardial sarcolemma (SL), thus a large quantity of extracellular Ca~(2+) fluxed over the SL to the intracellular space, forming a condition of intracellular Ca~(2+) overload, which leads to irreversible damage of the myocardium.