Sarcolemmal Na+-Ca2+ exchange activity in hearts subjected to hypoxia reoxygenation.

Although the occurrence of intracellular Ca2+ overload is known to be an important factor in hypoxia-reoxygenation injury, the exact mechanisms for this abnormality are not presently clear. Since Na+-Ca2+ exchange in the sarcolemmal membrane is considered to be involved in Ca2+ efflux, this study was undertaken to examine the effect of hypoxia reoxygenation on this system. Isolated rat hearts were made hypoxic by perfusing with a substrate-free medium gassed with 95% N2-5% CO2 and then reperfused with oxygenated normal medium.

Refractory heart failure and age-related differences in adriamycin-induced myocardial changes in rats.

Clinical use of adriamycin, an effective chemotherapeutic agent, has been restricted because of a demonstrated dose-limiting cardiotoxicity. To study age-related differences in adriamycin-induced cardiotoxicity, clinical status, developed force, ultrastructure, and lipid peroxide changes in the myocardium were investigated in two age groups of rats termed younger (Cy) and older (Co). Experimental animals (Cy + A; Co + A) received a cumulative dose of 15 mg/kg of adriamycin over 2 weeks.