Attenuation of mitochondrial, but not cytosolic, Ca2+ overload reduces myocardial injury induced by ischemia and reperfusion.

Aim: Attenuation of mitochondrial Ca2+ ([Ca2+]m), but not cytosolic Ca2+ ([Ca2+]c), overload improves contractile recovery. We hypothesized that attenuation of [Ca2+]m, but not [Ca2+]c, overload confers cardioprotection against ischemia/reperfusion-induced injury.

Methods: Infarct size from isolated perfused rat heart, cell viability, and electrically-induced Ca2+ transient in isolated rat ventricular myocytes were measured.