[Intracellular oxidative-reductive processes in tissues in hyperthermia]. / Vnutrikletochnye okislitel'no-vosstanovitel'nye protsessy v tkaniiakh pri gipertermii.

Experiments were conducted on male albino rats to study some intracellular metabolites (lactate, pyruvate, malate, glutamate, alpha-ketoglutarate, ammonia) and the redox process in the tissues of the liver, kidneys, myocardium, and skeletal muscles during hyperthermia (40 degrees C for one hour and 45 degrees C for one hour). Changes of the metabolite content and shifts in the redox process in the direction of oxidation in the liver and kidneys at both levels of hyperthermia are evidence of the development of tissue hypoxia of circulatory character in these organs. The mitochondrial NAD/NADH ratio in the myocardium reduced in moderate hyperthermia and increased during a heat stroke. There were no signs of cellular hypoxia in the skeletal muscles. It is concluded on basis of the results that changes of the blood flow in the organs play the leading role in the origin of thermal hypoxia.

[Change in the lipid composition of rat tissues in hyperthermia of varying degree]. / Izmenenie lipidnogo sostava tkanei krys pri gipertemii raznoi stepeni.

The most typical alteration of membrane phospholipids in rat tissues in acute hyperthermia was an increase in content of sphingomyelin and phosphatidylinositol. The increase in phosphatidylinositol appears to occur as a result of unspecific effect of hyperthermia on the cells, while the increase of sphingomyelin is apparently important for stabilization of membrane structure. Indirect data were obtained on increase in membrane liquidity during thermic shock.

[Transport of Ca2+ in the sarcoplasmic reticulum of skeletal muscles in hyperthermia]. / Transport Ca2+ v sarkoplazmaticheskom retikulume skeletnykh myshts pri gipertermii.

Study of functional changes in sarcoplasmic reticulum membranes of the rat skeletal muscles shows that mild hyperthermia is accompanied by the activation of Ca-transporting system function (the increase in accumulation of Ca ions and the rise of Ca(2+)-ATPase activity are observed), a passive release of this ion being unchanged. The revealed changes are regarded as reaction induced by the body temperature increase. The effectiveness of the SR Ca-pump decreases sharply under heat stroke, but the increase of Ca2+ release from SR vesicles is observed. This is considered to be one of possible factors, causing disorder of electromechanical coupling and the disturbance of the skeletal muscle contractility.

[Change in the lipid composition of the inner mitochondrial membranes in rat organs during adaptation to heat]. / Izmenenie lipidnogo sostava mitokhondrial'nykh membran vnutrennikh organov krys pri adaptatsii k teplo.

Under conditions of adaptation to heating lipid composition in mitochondrial membranes of rat inner tissues was altered as follows: an increase in relative concentration of plasmalogenous forms of phospholipids (kidney, heart) and in content of saturated fatty acids (liver tissue), a decrease in the index of fatty acids unsaturation and in the ratio of fatty acids omega-3/omega-6. The alterations observed enabled the membranes to keep sufficient amount of liquidity essential for functional activity of mitochondria in heating.

[The temperature dependence of the respiration and phospholipid content of the mitochondria in the organs of heat-adapted rats]. / Temperaturnaia zavisimost' dykhaniia i fosfolipidnyi sostav mitokhondrii organov u adaptirovannykh k teplu krys.

A shift of breaking point to higher temperatures was illustrated on Arrhenius plots in kidney, liver and heart mitochondria of heat-adapted rats on 4.1, 2.7, 2.4 degrees C respectively. Q10 mitochondrion respiration fall in adapted animals in a range of 26-36 degrees C was indicative of temperature compensation. It was shown the elevation of phospholipid plasmalogen form content in heart and kidney mitochondria; as well as saturated fatty acids content in liver mitochondria. Structure and function changes were suggested to be the basic point of elevation of mitochondrion functional ability at high ambient temperature.

[The effect of ionol on oxidative-reductive processes in the kidney during heat stroke]. / Vliianie ionola na okislitel'no-vosstanovitel'nye protsessy v pochke pri teplovom udare.

Heat stroke was induced in intact rats in a thermal chamber (45 degrees C) and simultaneously a group of animals was subjected to overheating for the same time but was given intraperitoneal injections of ionol (120 mg/kg) for 2 days and 30 minutes before exposure in the chamber. Significant increase of the concentration of intermediates--lactate, pyruvate, malate, glutamate, ammonia--and decrease of the alpha-ketoglutarate content occurred in the renal tissue in animals of both groups. The NAD/NADH ratio in the cytoplasm and mitochondria reduced essentially, to a greater degree in animals given ionol injections. The last named were distinguished by higher survival and lower degree of hyperthermia.