ADAPTIVE MODIFICATION<i> </i>OF AMINO ACID POOLS IN THE MYOCARDIUM OF THE LONG-TAILED GROUND SQUIRREL <i>UROCITELLUS UNDULATUS</i> AT DIFFERENT STAGES OF HIBERNATION

Abstract

The state of hibernation is characterized by increased resistance to the effects of prolonged deep hypothermia, hypoxia, lack of food and water. At the same time, the restructuring of the adaptive mechanisms of animals at low temperatures, even for a short time, causes significant changes in metabolism, reflected in the pattern of amino acids. The change in the metabolism of free myocardial amino acids during hibernation has not yet been studied by anyone, but the idea of it is necessary to understand the mechanisms of the hibernation state, which is relevant for clinical medicine. In this regard, the task of this work was to study the changes in the composition of free amino acids of the myocardium of the ground squirrel U. undulatus at different stages of hibernation. A negative interdependence of glutamic acid and alanine pools at different stages of torpor was revealed. The decrease in the level of glutamic acid compared to the summer control (5.08 ± 0.44 μmolе/g wet weight) began in the first, December bout, continued with prolonged torpor (up to 1.57 ± 0.14 μmolе/g) and was accompanied by a corresponding increase in the alanine pool. During the winter awakening, the glutamic acid pool rose above the summer level; The pool of alanine fell below the summer level, but their total level did not change. The pools of aspartic acid and glycine decreased in parallel with the decrease in pools of glutamate and aspartate, but during the winter awakening, glycine was not even detected. Taking into account the participation of glutamic acid and aspartate in the anaplerotic reactions of the Krebs cycle and the reciprocal relationship of glutamic acid and alanine, it is concluded that the change in the content of these metabolites at different stages of bouts is associated with a gradual transition of aerobic glycolysis (Krebs cycle and oxidative phosphorylation) to anaerobic, and during euthermia, on the contrary, with a return to aerobic.