Electrolytes of Damaged Myocardial Mitochondria 1

Summary

The concentrations of Mg²⁺, K⁺ and nitrogen in mitochondria isolated from dog myocardium after 2 and 3 hr of autolysis at 37° were significantly decreased from the control while the mitochondrial Ca²⁺ concentration showed a small apparent increase after 1 and 2 but not 3 hr of autolysis. Intramitochondrial dense bodies were found in the mitochondria isolated from damaged myocardium at all time intervals, but an increasing proportion of large mitochondrial fragments were isolated from the damaged tissue as the duration of autolysis increased, suggesting that the decreased nitrogen yield per unit quantity of heart was the result of increased mitochondrial fragility. These experiments do not finally establish whether the mitochondrial granules contain significant quantities of Ca²⁺, but do suggest that Mg²⁺ probably is not a significant constituent of the granules.