Akopova O V, Sahach V F
Ukr Biokhim Zh (1999). 2007 Jan-Feb;79(1):58-67.
The release of divalent cations (Ca2+ and Sr2+) from rat liver mitochondria after membrane depolarization with protonophore (carbonyl cyanide m-chlorophenyl hydrazone, CCCP), sodium azide and K(+)-ionophore (valinomycin) was studied. It is stated that membrane depolarization itself is not sufficient for cations release from mitochondrial matrix (provided that mitochondrial permeability transition pore is blocked by cyclosporin A). Complete delivering of divalent cations is observed only after protonophore (CCCP) addition to suspension of deenergized mitochondria. The data show that membrane permeabilisation to hydrogen ions (H+) is necessary for complete cation release from the mitochondrial matrix. The enhancement in K(+)-conductivity of mitochondrial membrane (by valinomycin), on the contrary, is not able to provide complete delivering of cations from mitochondria. It is shown that quantity of divalent metal cation released from mitochondria (depolarized and permeabilized for K+ as well) is proportional to the concentration of protonophore (but not K(+)-ionophore) introduced in the incubation medium. The data obtained lead to the conclusion that H(+)-permeabilization of the mitochondrial membrane is necessary for the complete release of Ca2+ and Sr2+ from mitochondria after membrane depolarization. The possible mechanism of divalent metal cations release from deenergized mitochondria is discussed.
研究了用质子载体（羰基氰化物间氯苯腙，CCCP）、叠氮化钠和钾离子载体（缬氨霉素）使大鼠肝线粒体膜去极化后二价阳离子（Ca2+和Sr2+）的释放情况。研究表明，膜去极化本身不足以使阳离子从线粒体基质中释放出来（前提是线粒体通透性转换孔被环孢菌素A阻断）。只有在向去能线粒体悬浮液中加入质子载体（CCCP）后，才观察到二价阳离子的完全释放。数据表明，线粒体膜对氢离子（H+）的通透性对于从线粒体基质中完全释放阳离子是必要的。相反，线粒体膜钾离子电导率的增强（通过缬氨霉素）并不能使阳离子从线粒体中完全释放。研究表明，从线粒体（对钾离子去极化并通透）释放的二价金属阳离子的量与孵育介质中引入的质子载体（而非钾离子载体）的浓度成正比。所得数据得出结论，线粒体膜的H+通透性对于膜去极化后从线粒体中完全释放Ca2+和Sr2+是必要的。讨论了去能线粒体中二价金属阳离子释放的可能机制。
