
<ArticleTitle>Hypoxia delays the intracellular Ca2+ clearance by <prot>Na+-Ca2+ exchanger</prot> in human adult cardiac myocytes.</ArticleTitle>
<AbstractText>Transient myocardial ischemia during cardiac surgery causes a loss of energy sources, contractile depression, and accumulation of metabolites and H+ ion resulting in intracellular acidosis. The reperfusion following ischemic cardioplegia recovers intracellular pH, activates Na+-H+ exchange and Na+-Ca2+ exchange transports and consequently produces Ca2+ overload, which yields cell death. Among the various Ca2+ entry pathways, the <prot>Na+-Ca2+ exchanger</prot> is known to play one of the major roles during the ischemia/reperfusion of cardioplegia. Consequently, information on the changes in intracellular Ca2+ activities of human cardiac myocytes via the <prot>Na+-Ca2+ exchanger</prot> is imperative despite previous measurements of Ca2+ current of human single myocytes. In this study, human single myocytes were isolated from the cardiac tissues obtained during open-heart surgery and intracellular Ca2+ activity was measured with cellular imaging techniques employing fluorescent dyes. We report that the <prot>Na+-Ca2+ exchanger</prot> of adult cardiac myocytes is more susceptible to hypoxic insult than that of young patients.</AbstractText>
