[Ion transport in rat liver mitochondria after freezing and thawing].

Induction of ion transport in the rat liver mitochondria arising after their deep freezing is inhibited effectively by adenosine diphosphate, Mg ions, Ca2+ complexons (EDTA, EGTA) as well as by inhibitors of ATPase (oligomycin and dicyclohexylcarbodiimide) and of electrogenic transport of Ca2+ (ruthenium red). The value of ion flows is determined by adenine nucleotide concentration in the matrix. It is supposed that specific inhibitors of ion electrogenic transport promoting an increase in the transmembrane potential prevent from releasing adenine nucleotides from the mitochondrial matrix.

[The role of lipolysis and lipid peroxidation in the induction of ion transport in mitochondria after freezing and thawing].

The reasons of ion transport induction observed after freezing-thawing of the rat liver mitochondria were investigated. It is found that a fall in the membrane potential value, an increase in the respiration rate and K+ ion release from mitochondria to the incubation medium with phosphate are averted when succinate is replaced by the Kreb's cycle substrates and when ionol (an antioxidant) or nupercain (an inhibitor of mitochondrial phospholipase A2) are incorporated into the incubation medium. The induction of ion transport is caused by the activation of peroxide processes and of lipolysis associated with them.

[Structural and kinetic parameters of the oxidative phosphorylation system, participating in the synchronization of mitochondrial respiratory chain and ATP-synthetase functions].

The structural and kinetic parameters of the oxidative phosphorylation system responsible for synchronization of the respiratory chain and ATP-synthetase function in mitochondria were studied. It was shown that regulation of ATP-synthetase function by the respiratory chain can be realized only within the whole ATP-synthetase complex (F0F1). NADH dehydrogenase and succinate dehydrogenase doe not control synchronization of ATP-synthetase function in the mitochondria.

[Regulation of ion transport in mitochondria by respiratory chain enzymes and ATPase].

The effects of the respiratory chain inhibitors as well as those of the inhibitors and substrates of ATP-synthetase in Ca2+ and K+ transport induced in the mitochondria upon the medium acidification in the presence of phosphate or arsenate, were investigated. Evidence has been obtained suggesting that under the experimental conditions used the transmembrane fluxes of K+ and Ca2+ are paralleled with H+ leakage through the proton channel of ATPase. It was found also that the system inducing cation fluxes at low pH values included peroxidation and hydrolysis of phospholipids.

[Synchronization of the function of respiratory chain enzymes and ATP-synthetase in energized mitochondria].

The present study revealed that the previously described effect of ATP-synthetase inhibition concomitant with inhibition of the respiratory chain functioning could be observed under different absolute values of delta phi on the mitochondrial membrane. This points out that the membrane potential is not a unique regulator in the coupling of the ATP-synthetase and respiratory chain activities. At the same time, we succeeded in obtaining some evidence testifying that under conditions of ATP-synthetase inhibition the amount of functioning respiratory chains has to be proportional the functioning of the ATP-synthetases units.