[Relationship between the depth of acute hypothermia and the composition and phase transitions of mitochondrial lipids of dog and white rat myocardium].

It has been found in the experiments on white rats and dogs that the increase of body temperature by 8--10 degrees in myocardium mitochondria composition of phospholipids is changed, microviscosity of lipids decreases, the phase transition is shifted to the low temperature region. Changes in white rats' mitochondria are expressed to a greater extent. When the body temperature is decreased by 18--20 degrees microviscosity of lipids in dog myocardium mitochondria increases, that of white rats is maintained on the same level. Effect of the composition of membrane lipids on the temerature of phase transitions during hypothermia is discussed, as well as possible dependence of the stability of animals towards low temperatures on the degree of reconstruction of the membrane lipids.