Khalilov R.A., Jafarova A.M., Abdullayev V.R., Abakarova Sh.A. EFFECT OF TEMPERATURE ON THE FUNCTIONAL CHARACTERISTICS OF THE KEY ENZYME OF ENERGY METABOLISM OF SKELETAL MUSCLES OF SMALL GROUND SQUIRRELS (SPERMOPHILUS SPYGMAEUS PALL.) OF STEPPE ECOSYSTEMS // Arid ecosystems. 2021. V. 27. № 2 (87). P. 98-105 | PDF

Significant seasonal temperature fluctuations in the arid zones of Northwestern Dagestan determine their wide population of heterothermal mammals, which have a unique ability to fall into a state of hibernation at low ambient temperatures. Significant fluctuations in physiological and biochemical processes during and after hibernation suggest that heterotherms have flexible mechanisms for changing the functional characteristics of key metabolic enzymes. In this paper, the temperature dependence of LDH activity of skeletal muscles of small ground squirrels Spermophilus pygmaeus Pall was studied during the period of summer wakefulness, deep hibernation and at various stages of awakening, accompanied by warming up the body of animals to temperatures of 10°C, 20°C, 30°C, 37°C. It was found that in hibernating ground squirrels, the activity of LDH, regardless of its incubation temperature in vitro, significantly decreases. In the dynamics of warming, there is an increase in the activity of LDH, the progressive nature of which is most pronounced in the range of body temperatures of animals 1.6 20 20°C. The temperature dependence of LDH activity in Arrhenius coordinates is approximated by non-linear graphs, the inflection position of which during hibernation shifts to the low temperature region, and after full warming up again takes control values. Hibernation contributes to a significant increase in the energy and enthalpy of LDH activation. In the dynamics of warming, the levels of these parameters are disproportionately reduced, reaching the control values of summer animals. The obtained data support the assumption that in the skeletal muscles of ground squirrels during hibernation and at various stages of awakening, significant changes in the mechanisms of LDH catalysis occur, which have an adaptive character.

Keywords: hibernation, awakening, ground squirrels, muscles, lactate dehydrogenase, temperature dependence, activation energy, activation enthalpy.

DOI: 10.24411/1993-3916-2021-10155