Yonsei Med J.  2001 Jun;42(3):333-337. 10.3349/ymj.2001.42.3.333.

Hypoxia Delays the Intracellular Ca2+ Clearance by Na+ - Ca2+ Exchanger in Human Adult Cardiac Myocytes

• Park SI
• Park EJ
• Kim NH
• Baek WK
• Lee YT
• Lee CJ
• Suh CK

• KMID: 720630
• DOI: http://doi.org/10.3349/ymj.2001.42.3.333

Abstract

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 Na+-Ca2+ exchanger 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 Na+-Ca2+ exchanger 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 Na+-Ca2+ exchanger of adult cardiac myocytes is more susceptible to hypoxic insult than that of young patients.

Keyword

Human; Na+-Ca2+ exchanger; hypoxia; adult cardiac myocytes

MeSH Terms

Adult
Anoxia/*metabolism
Calcium/*metabolism
Child
Child, Preschool
Female
Human
Hydrogen-Ion Concentration
Infant
Male
Middle Age
Sodium-Calcium Exchanger/*physiology