[Effect of monovalent cations on calcium transport in the mitochondria]

Radioisotope exchange was used to study the effect of the Na+/K+ ratio on Ca2+ absorption and release from mitochondria of the rat myocardium, brain and fatty tissue. The increase in Na+ concentration in the incubation medium containing ATP and succinate leads to a 8-fold reduction of the Ca-accumulating capacity of brain mitochondria (K0,5 for Na+ 7 and 30 mM, respectively). A mechanism is suggested that explains the possibility of the Na-dependent regulation of the Ca-accumulating capacity of mitochondria of the tissues under consideration.