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The influenc of cholesterol on the formation of the mitochondrial cyclosporin A (CsA)-insensitive palmitate/Ca(2+)-activated pore has been studied. It has been established that increasing the cholesterol level in mitochondrial membranes results in an increase in the of rate of mitochondrial swelling induced by palmitic acid (> or = 20 microM) and Ca2+ (30 microM). This effect is not related to changes in the functional activity of organelles since cholesterol did not influence the mitochondrial respiration in different metabolic states. At the same time, it was shown that the palmitate/Ca(2+)-induced permeabilization of cholesterol-containing azolectin liposomes was Stronger than that of azolectin liposomes. It was found that, in the liposomal membrane, the Ca(2+)-induced phase separation of palmitic acid into distinct membrane domains takes place. The presence of cholesterol in membranes increases the extent of segregation.

The influence of taurine on the ATP-dependent mitochondrial swelling, which characterizes the activity of the ATP-dependent K+ channel and the opening of Ca(2+)-dependent pores differing in the sensitivity to cyclosporin A in rat liver mitochondria has been studied. It was shown that taurine at small (0.5-125 microM) concentrations produces a stimulating effect on the ATP-dependent mitochondrial swelling. Taurine in physiological concentrations (0.5-20 mM) di not affect the ATP-dependent mitochondrial swelling and cyclosporin A-insensitive palmitate/Ca(2+)-activated pore formation in mitochondria. Taurine in these concentrations increased the rate of cyclosporin A-sensitive swelling induced by Ca2+ and P(i) and decreased the Ca2+ capacity of mitochondria.

The structure of mitochondrial cristas has been studied for the first time by the method of small-angle scattering of thermal neutrons. Experiments were performed on intact functioning rat liver mitochondria. Mitochondrial cristas are usually considered as folds of the internal membrane with arbitrary nonfixed intermembrane distances. It was shown that, under particular conditions, during low-amplitude swelling of mitochondria, cristas are transformed to bimembrane structures, with the distance between the central planes of membranes of 190 E. It was found that the formation of bimembrane structures and their structural parameters do not depend on the method of induction of swelling, by placing the mitochondria into a hypotonic medium or by the opening of nonspecific pores.

The ultrastructure of liver cells was studied in rooks (Corvus frugilegus) living in radioactive and chemical contamination areas. The ultrastructure of liver cells from rook as well as jackdaw (Corvus monedula) and hooded crow (Corvus cornix) (Corvidae family) from a conventionally clean area was studied as control. Control hepatocytes proved to contain a great number of mitochondria, many of which were swollen and had clear matrix and disorganized cristae. The cristae nearly lacked glycogen and had abundant lipid droplets, which often tightly contacted mitochondria. The cytoplasm of hepatocytes in birds from both ecologically unfavorable areas had numerous mitochondria with the same ultrastructure. In contrast to control, the hepatocyte cytoplasm: (1) contained a lot of glycogen; (2) there were many lipid droplets, which directly contacted glycogen granules; and (3) had more abundant peroxisomes. In addition to normal erythrocytes, the sinusoids contained erythrocytes with mitochondria, vesicles, and lipid droplets in their cytoplasm. Analysis of many micrographs of lipid droplets contacting glycogen granules, mitochondria, peroxisomes, and cisterns of smooth endoplasmic reticulum allowed us to propose that glycogen is synthesized via gluconeogenesis from glycerol and products of fatty acid oxidation in the liver cell cytoplasm of rooks from ecologically unfavorable areas as distinct from control.

Hypertrophied mitochondria (Mt) were found in the sensorimotor cortex neurons under prolong low-frequency vibration in the experiment with 66 white rat males. Structural changes of Mt were similar to those shown under other types of stress accompanied by energy supply deficit. The results indicated that the reaction of the Mt population on low-frequency vibration has stages and lead to formation of uniformity in structural and functional properties of Mt regardless of the neurons type.

The investigations revealed that long term action of vibration causes the following changes: growth of mitochondria size (the appearance of hypertrophied ones) clearing of their matrix, vacuoles formation, destruction of cysts. Similar changes were described in extreme conditions connected with deficiency of energy supply. Reaction of mitochondrial population to the action of vibration is phased and lies in change of relative content of mitochondria with different functional activity (orthodoxal, activated and destroying). General direction of these reorganization is a creation of stable and reactive functional subcellular system.

It has been shown that the increase of the membrane potential in uncoupled brown fat mitochondria after addition of 1-2 mM GDP to a medium containing potassium acetate is accompanied by swelling of mitochondria which occurs in two phases. The first swelling phase is due to the electrogenic transport of K+ ions, while the second one is activated by carboxyatractylate and carnitine. The swelling is practically completely inhibited by a further rise of the GDP concentration irrespective of high values of the membrane potential. Unlike K+ transport, the potential-dependent transport of Na+ ions occurs more rapidly, is monophasic and insensitive to carboxyatractylate and carnitine. It is suggested that regulation of K+ ion transport in brown fat mitochondria is mediated by the action of nucleotides and fatty acid esters on the uncoupling protein and ADP/ATP antiporter.

Hyperosmotic shrinkage and hypoosmotic swelling of the internal mitochondrial membrane decrease considerably the efficiency of the reaction of the cyanide photodissociation from the cytochrome oxidase. The osmotic effect increases after the reduction of the membrane potential by a protonophore uncoupler. This suggests that the local photochemical reaction is subject to membrane control.

Studies of swelling of rat liver mitochondria in isoosmotic solutions of nonelectrolytes in the presence of respiration inhibitors revealed that submicromolar concentrations of Ca2+ increase the diameter of pores in the inner mitochondrial membrane--from 5.5-6.0 A (10(-8) M Ca2+) up to 7.5 A (3 x 10(-7) M Ca2+) and 8.0-8.5 A (6 x 10(-7) M Ca2+); these increases are prevented by cyclosporin A. The inner mitochondrial membrane with an effective pore diameter of 7.5 A is readily permeable for potassium but not for sodium ions, although with an increase in the effective pore diameter up to 8.0-8.5 A the selectivity of the K(+)-Na+ channel decreases. A conclusion is drawn that in the presence of submicromolar concentrations of Ca2+ the conductivity of the cyclosporin-sensitive pore for monovalent cations increases in the following order: K > Na > Li.

A comparative analysis of delta psi of liver mitochondria of active and hibernating gophers was carried out, and the effect of the decrease of the medium tonicity on the oxidase activity and delta psi of liver mitochondria of both animal groups was studied. The delta psi of hibernating gopher liver mitochondria was shown to be lower than that of active animals mitochondria and displayed a higher sensitivity to the uncoupler and some different restoration dynamics after the decline following the ADP addition. Swelling of liver mitochondria of hibernating gophers in hypotonic media or in media containing potassium acetate and a 3-fold freeze-thawing procedure resulted in the enhancement of the oxidase activities accompanied (in case of hypotonicity) by an delta psi increase and a decrease of its sensitivity to the uncoupler, 2.4-dinitrophenol. Inhibition of phospholipase A2 prevented the enhancement of the oxidase activity in all cases and the delta psi increase in hypotonic media.

Activation of initially suppressed oxidative phosphorylation and energy-dependent uptake of Ca2+ and K+ ions by liver mitochondria of hibernating gophers which is prevented by phospholipase A2 inhibitors, has been shown to occur in hypotonic media. Partial inhibition of the respiratory chain of liver mitochondria of active gophers by antimycin A which causes a decrease in the uncoupled respiration rate and delta psi down to values typical of mitochondria of hibernating gophers, practically exactly reproduced the suppression of oxidative phosphorylation and energy-dependent uptake of cations observed during hibernation. It was concluded that partial deenergization arising as a result of inhibition of the respiratory chain is the main and unique cause of suppression of energy-dependent functions of liver mitochondria of hibernating gophers.

The effects of some parameters of the incubation medium (tonicity, H+ and Pi concentration) on the phospholipid content in rat mitochondrial extracts prepared by normal extraction and by extraction with strongly acidified solvent mixtures, were studied. It was found that after normal extraction with a chloroform-methanol mixture, 8% to 25% of mitochondrial phospholipids can be additionally extracted by acidified solvent mixtures. The concentration of weakly extractable lipids depends on the tonicity and ionic composition of the incubation medium. It was suggested that there exist in mitochondria two lipid pools, a loosely and a tightly-bound ones; the equilibrium between these pools is effectively regulated by medium tonicity and other external factors.

The rate of respiration and ATP synthesis in liver mitochondria (M) isolated from hibernating ground squirrels and incubated in the medium with normal tonicity (250 mosm) was shown to be considerably lower than the rate of respiration and ATP synthesis in liver M from active animals. The increase of the medium tonicity to 600 mosm simulated the state of M from hibernating animals, resulting in a decrease of the respiration rate of M from active ground squirrels. On the contrary, the decrease of the tonicity to 60 mosm caused the activation of the respiration and increase of the ATP synthesis in M from hibernating ground squirrels. Bromophenacylbromide (BPhB), an inhibitor of phospholipase A2, prevented the activation of the respiration of M from hibernating animals incubated in the medium with low tonicity. BPhB had practically no effect on the respiration of M from both hibernating and active ground squirrels as well as on the swelling of M in hypotonic medium. It was concluded that the activation of the respiration and increase of the ATP synthesis rate in M from hibernating ground squirrels incubated in the medium with low tonicity is related to the activation of phospholipase A2. It was assumed that decrease of phospholipase A2 activity and change in the lipid composition of mitochondrial membrane may be one of the reasons for inhibition of the respiration rate in M from hibernating ground squirrels.

During experimental allergic encephalomyelitic (EAE) in dogs, it was established with electron microscope that mitochondria of neurons and glia of the central nervous system (CNS) were most sensitive organelles to the development of neuroallergy. Swelling of mitochondria, disruption of their membranes, desorganization of mitochondrian cristae were observed in the incubation period; these alterations were seen increasing by the moment of clinical manifestation of EAE. Immunization of guinea pigs by mitochondrial fractions of dog's brain cortex with Freund's adjuvant resulted in the manifestation of clinical and morphological signs of EAE in the CNS in addition to a significant destruction of mitochondria. The idea of the initial alteration of different membranous structures of the CNS during demyelinating processes in brain is put forward.

Structure of capillaries, pericapillary glia and neurons of the sensomotor cerebral cortex was studied in rats after intraperitoneal injections of angiotensin-II (0.05 mg/kg of the body weight) administered once for 1, 3, 7, 14 and 21 days. The animals were decapitated 5 and 15 min after a single injection, and at repeated injections--15 min after the last one. The repeated injections of angiotensin-II were stated to produce a stable edematous syndrome in the brain of the animals. Pericapillary (astrocytic) glial edema was associated with neural cells edema. The more angiotensin-II was injected, the greater was dilatation of astrocytic processes adjoining the capillaries. In some edematous neurons it was cytoplasmic matrix that swelled, in others--liquid was accumulated in the cytoplasmic network cavities. Membrane bodies appeared in the capillary endothelial cells and in neurons made also a peculiar feature. It could be possible that functional shifts in the CNS observed after repeated injections of angiotensin-II were resulted from deficiency of the cerebral circulation and some structural changes in neural and glial elements.

Disturbances typical of experimental allergic encephalomyelitis (EAE) are determined to be formed already in the initial period of sensibilization. In the spinal cord the lesions appeared relatively earlier than in the brain. Just before the neurologic manifestations of EAE a deep destruction of some myelinized axons and phagocytosis of myelin by oligodendrocytes are registered in the brain and spinal cord structures. Alterations in neurocytes and degeneration of synapses of the light type are characteristic.

Compartmentalization of Ca2+ was studied in homogenates and subcellular fractions (nuclei, mitochondria, microsomes and cytosol fraction) of rat liver tissue under conditions of chemical lesion of hepatocyte membranes caused by CCl4. The studies were carried out within 2, 24, 48, 96 and 168 hrs after the CCl4 administration. The chemical lesion of hepatocyte membranes led to considerable increase in Ca2+ concentration in the subcellular fractions studied, especially in cytosol fraction, where it reached about 424% as compared with the control level. The drastic increase of calcium concentration in cytosol appears to be due to disturbance of both Ca2+ elimination through plasmatic membrane and its mitochondrial sequestration.

The initial rate (v) versus initial substrate concentration [S]0 plots for the reaction of serotonin deamination catalyzed by rat liver mitochondrial monoamine oxidase are characterized by complicated non-hyperbolic patterns. The shapes of the curves in the plots depend on the age and strain of the animals used or on alterations in the physico-chemical state of mitochondria caused by freezing -- thawing and swelling in hypotonic solutions. The v versus [S]0 plots for other substrates (e. g. tyramine) do not obey the Michaelis -- Menten equation as well. In order to interpret the kinetic patterns described a model of the mitochondrial monoamine oxidase structure and function has been proposed. The model is based on the assumption that both catalytic and regulatory allosteric sites are present on the surface of monoamine oxidase molecules. In the process of serotonin or tyramine binding the monoamine oxidases exhibit cooperative properties which are characteristic for the allosteric enzymes. The model also suggests an active regulatory role of the mitochondrial membrane itself.

Mitochondrial swelling in hypotonic sucrose solutions is accompanied by a decrease of the amount of phosphatidyl ethanolamines, cardiolipids and their lyso-derivatives. An addition of dicaine (inhibitor of phospholipase) to the incubation medium results in a considerable decrease of mitochondrial swelling and prevents the decay of phosphatidyl ethanolamines and cardiolipids. This effect is due to the inhibition of corresponding phospholipases. The data obtained suggest that the passive mitochondrial swelling is accompanied by activation of endogenous phospholipases and by a hydrolysis of cardiolipids, phosphatidyl ethanolamines and their lyso-derivatives.

Experiments on rats under 30-day hypokinesia have shown an increase in the mitochondrial area in perinuclear, myofibrillar and subsarcolemmal zones of the cardiomyocyte pericaryon, accompanied by a concurrent rise in the number of crests. The crest density index and the amount of mitochondria in te pericaryon diminish. These changes are considered as compensatory-adaptive reconstitution of hypertrophic nature in response to partial destruction of mitochondria. During the observation period this reconstitution is not completed and thus underlies the decreased contractility and functional reserves of the heart in hypokinesia.

Prolonged exposure to sound (1-12 hr, 100-120 db, 2000-4000/sec) resulted in morphological changes in the receptor cells of the guinea-pig spiral organ. These changes were found to depend on the sound exposure time. A restoration time is proportionate to the time and intensity of the sound stimulus.

In 212 male rats (200-250 g) ultrastructure of gastric parietal glandulocytes has been studied at various levels of the thyroid hormones in the organism. At experimentally produced hyperthyrosis a definite direct dependence has been noted to exist between the developmental stage of mitochondrial membranes (cristae), mitochondrial enzymes activity and the level of hydrochloride acid secretion. At hypothyrosis, the gastric parietal cells have signs of low differentiation--large number of cisterns in the granular cytoplasmic network and lack of tubulovesicles are noted.

Scanning electron microscopy has revealed three types of myocardial mitochondria degradation in intact rabbit heart: desquamation of the external membrane, mitochondria swelling with their following destruction, mini-focal ulceration of mitochondrial external membranes. There was a clear-cut daily and seasonal dynamics of the three types of degradation. Mitochondria degradation was much more pronounced in the fibrillating than in intact heart.

An examination of the cerebral cortex of rats exposed to sublethal doses of potassium cyanide has revealed changes in the neurons characteristic of the developing histotoxic hypoxia. The neurons of the large hemisphere cortex showed a pronounced hydropic reaction in their cytoplasm with prevalent involvement of the mitochondria. This form of the pathology was observed irrespectively of the duration of the animals live after the poisoning. In rats which survived for a longer time there appeared hyperchromic neurons the number of which gradually increased. This fact was interpreted as addition of the hypoxic state of the neurons to the cyanide intoxication: this was confirmed by development of signs characteristic of hypoxic hypoxia at this stage. The degree of the changes in the mitochondria was found to correlate with the depth of the impairment of vitally important neuron structures. The data obtained show that the primary morphological changes in the neurons develop in their cytomembranes. The degree of the impairment of the mitochondrial membranes can serve as a criterion of reversibility or irreversibility of the pathological process in the nerve cells.

It was shown in experiments in vitro that high density lipids (HDL), very low density lipids (VLDL) and cAMP taken separately did not affect the kinetics of mitochondrial swelling in the liver of control and 72-hr-fasting rats. ApoHDL and particularly ApoVLDL obtained by delipidation of appropriate lipoproteins had pronounced capacities to stimulate the process of swelling. Mitochondrial swelling increased to an ever greater degree under the action of cAMP coupled with apoproteins. The maximum stimulation of the swelling was attained as a result of administering apoVLDL in conjunction with cAMP. The effects of enhanced swelling were the most remarkable in experiments with mitochondria from the control animals.

Histological and ultrastructural alterations in the lung parenchyma of rats with sepsis induced by implantation of 3 X 10(10) microorganisms (P. aeruginosa) beneath the skin were studied. Microorganisms with micropili were detected in septal spaces and in the alveoli 10 hours after implantation. Their effects were linked with microcirculatory alterations and destruction of endotheliocytes, alveolocytes and septal cells.

Ultrastructure of rabbit heart left ventricle isolated according to Langendorf was examined under different conditions: in intact animals, during ligation of the coronary artery, and hypoxic heart perfusion. The intact perfused heart showed unmarked exo- and intracellular edema and moderate swelling of the mitochondria. During hypoxic perfusion, marked swelling and destruction of the mitochondria were noted. During ligation of the coronary artery, the heart was characterized by a high degree of mitochondrial heterogenicity. The correlation of the data obtained allowed one to reveal the myocardial adaptive-accommodative mechanism, (intermittent mitochondrial activity) that makes it possible to maintain the heart bioenergetics during coronary artery occlusion at a permanently high level.

The myocardium of the left and the right cardiac ventricles was studied at various seasons on 20 rabbits. There was found a distinct seasonal dynamics of a number of quantitative indices of electronograms. In particular, there was found a relationship between the coefficients of energy efficacy of the mitochondria (integral value--calculated by multiplying the mitochondrial area by the number of mitochondrial cristae) and the mitochondrial area. With increase of the latter to 0,85 mc2 this relationship is positive and linear. With further swelling of the mitochondria this relationship disappears, however.

Using electron microscopy, no significant alteration were revealed in the boar spermatozoa suspended for 0.5-1 hour in the medium containing protective stuff except some desquamation and disruption in the spermatozoon head region. Similar picture was seen after a 3 hours' treatment in the medium. However, after freezing (-196 degrees C) and thawing more significant structural changes appear, at first part, in the head membrane structures. In addition, fragmentation and swelling of mitochondria is observed possibly accounting for the lack of spermatozoa motility after thawing.

Ca2+ ions are responsible for impairment of oxidative phosphorylation in rat liver mitochondria under anoxia in vitro. The decrease in this function is due to inhibition of electron transport over respiratory chain and to uncoupling. The increase in membrane permeability for H+, K+ and Na+ was observed on incubation of mitochondria under anoxic condition together with Ca2+. Uncoupling of phosphorylation depends on the increased permeability of the membranes for H+. The increased permeability of membranes for Na+ and K+ under energy liberation and in presence of penetrating anions led to active swelling of organelles and to secondary (osmotic) impairment. Ca2+-activated mitochondrial phospholipase A2 appears to participate in the organelle impairment under anoxia.

Interaction of cytochrome c with electron carriers in intact and damaged (with destroyed outer membrane) rat liver mitochondria was studied. It was shown that the increase in ionic strength causes changes in the respiration rate of damaged mitochondria due to the reduction of the cytochrome c affinity for its binding sites in the organelles. This suggests that cytochrome c concentration in the intermembrane space of intact mitochondria is increased by salts, whereas the increase in ionic strength has a slight influence on the rates of succinate oxidase and external rotenone-insensitive NADH-oxidase of intact mitochondria. At low ionic strength values, the Michaelis constant (KM) value of external NADH-oxidase for cytochrome c exceeds by one order of magnitude that for succinate oxidase, while the maximal activity of these two systems is nearly the same. The increase in ionic strength causes an increase in the KM value for both oxidases. Interaction of cytochrome c with mitochondrial proteins was modelled by cytochrome c interaction with cibacron-dextran anions. It was concluded that the ionic strength-sensitive electrostatic interactions play a decisive role in cytochrome c binding to electron carriers in mitochondrial membranes. However, cytochrome c content and its binding parameters in intact-mitochondrial membranes prevent the latent activity of external NADH oxidase to be revealed in intact mitochondria after the increase in the ionic strength of the surrounding medium.

Ultrastructural studies of cardiomyocytes during experimental aorta coarctation enabled one to divide them into 6 types: with mitochondrial swelling and enlargement of the sarcoplasmic reticulum; with primary damage to myofibrils; with disintegration of ultrastructure because of edema; with hypertrophy and hyperplasia of ultrastructures; without essential changes in organelles; and with concomitant changes in mitochondria and myofibrils. Such different reactions of cardiomyocytes are regarded as an adaptation mechanism that ensures the maintenance of heart function under extreme conditions.

Cells of the Unio tumidus gill ciliated epithelium were exposed to a supraoptimal temperature of 40 degrees C for the period from 30 seconds till a complete cessation of ciliar beating. ATPase activity of mitochondria of these cells being checked against their size during the corresponding period. The mitochondria were found to change their size in a phasic manner, swelling at the beginning of the temperature exposure, then shrinking and then swelling again. The ATPase activity increased during the first swelling and during shrinking to the control level. The data obtained indicate that similar ultrastructure and size of mitochondria may correspond to different levels of their functional activity.

A comparison has been carried out of osmotic properties of light and heavy synaptosomal fractions and a mitochondrial fraction from the rat brain cortex. A critical change is the rate of swelling at a definite time, allowing to subdivide the process into two phases, was shown. Throughout the swelling, its rate for heavy synaptosomes and mitochondria was much higher than that for the light ones. According to the initial rate of swelling in isoosmotic glycerol, the fractions examined can be arranged in the following order: mitochondria < light synaptosomes < heavy synaptosomes. Both total, light and heavy synaptosomes reveal the properties of ideal osmometers. The osmotic properties of synaptosomes and mitochondria are largely dependent on pH of the medium: with a shift towards acidic values of pH the swelling rate decreases to increase at more alkaline values. Especially well-pronounced changes occur at pH 6.8 and pH 7.3.

The authors studied the effect of thymectomy on the function of the mitochondria isolated from male rat liver. Six to 12 months after thymectomy there was a decrease in the activity of proton ATPase of the liver mitochondria as compared with a respective control group. According to the data obtained an increase in proton conduction of the external mitochondrial membrane plays an important role in the mechanism of the above-described changes.

The experiments have been performed on 24 guinea pigs (48 labyrinthes), 6 of them--control and 18 have been subjected to noise (one octava) with the average geometrical in diaposone of 2,000 Hz, at intensity level 100 dB. Six animals are subjected to a single effect for 6 h and 12--to repeated effect during 6 days running, 4-6 h daily. Isolation of both the vestibular and the cochlear parts of the membranous labyrinth is performed simultaneously. This gives a possibility to study all the receptors of the internal ear as a whole. Certain ultrastructural changes in all the vestibular receptors both at a single and repeated effects are revealed. Dilatation of the granular endoplasmic reticulum is observed, situating mainly in the basal part of the cell; swelling of mitochondria is accompanied with a sharp clearance of their matrix. In some mitochondria there is a local destruction of their external and internal membranes. Moreover, in cytoplasm of the receptory cells sharply osmiophilic fibrillar structures are revealed, they resemble crists and are arranged in bundles. In some cells they are not numerous and localize mainly in mitochondria, in others--their number is greater, and they localize not only in mitochondria, but in the surrounding cytoplasm, too. Similar structures are observed in some preganglionic myelin fibers. These phenomena can be considered as development of calcification processes. The changes described, evidently, form the basis of the vestibular disorders under the noise effect.

The myocardium of the left ventricle of intact rabbit was investigated by scanning electron microscopy during 24 hours, namely at 0, 6 a.m., noon and 6 p.m. It was discovered that the mitochondria reach the maximal volume at 6 p.m. and the minimal at 6 a.m. The qualitative differences in the mitochondria at different periods of the day are described. A correlation was established between the swelling of the mitochondria and some indices of heart function.