CHARACTERISTICS OF SR2-INDUCED PERMEABIL ITY INCREASE IN THE INNER MITOCHONDRIAL-MEMBRANE()

Ion-selective electrodes were used to study the Ca2+- and Sr2+-induced permeability transition of the inner membrane of rat liver mitochondr ia. It has been shown that accumulation of Ca2+ and Sr2+ into matrix o f mitochondria was accompanied by a transient and reversible increase of the membrane permeability to K+ and H+ ions. The Ca2+ and Sr2+ effl ux under these conditions was a result of this ion flux reversion thro ugh the potential-dependent uniporter system. Contraction of mitochond ria under jump of the sucrose concentration was nearly equal at a low and high permeability state of the inner mitochondrial membrane. Varia tions in the light scattering showed that sucrose and other osmoticall y active substances did not penetrate into the mitochondrial matrix.