N L Avetisova | PubMed Health

PubMedDate not supplied

[Transport of Ca2+ in the sarcoplasmic reticulum of skeletal muscles in hyperthermia].

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.

Adenosine Triphosphate↗

PubMedDate not supplied

[Intracellular oxidative-reductive processes in tissues in hyperthermia].

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.

Animals↗