CALCIUM-ACCUMULATING ABILITY OF RAT LIVER MITOCHONDRIA DURING HYPOTHERMIA OF VARIOUS DURATIONS

Abstract

Calcium is one of the most important intracellular messengers that regulate physiological and biochemical processes in the cell. Mitochondria are able to deposit calcium ions and are involved in the regulation of the calcium signal. Hypothermic conditions in homoiothermic animals can lead to disruption of this important function of mitochondria and pathological consequences. The aim of this study is to study the effects of moderate (30°C) hypothermia of varying duration on the calcium-accumulating capacity of rat liver mitochondria. The experiments were carried out on male rats Wistar. Hypothermia was induced by external cooling of the animals in Plexiglas chambers with a jacket through which cold water circulated. Mitochondria were isolated from the liver of decapitated rats by differential centrifugation. The calcium-accumulating capacity of mitochondria was assessed by the kinetics of calcium-induced swelling of mitochondria and their calcium capacity. A study of the kinetics of calcium-induced swelling of mitochondria showed that during short-term moderate (30°C) hypothermia, the rate of swelling of mitochondria decreases, prolongation of hypothermia to 1 h contributes to a further decrease in the swelling rate, and to 3 h, its normalization. A positive correlation was found between the rate of calcium-induced swelling and the calcium capacity of mitochondria (r = 0.79). Thus, with prolonged exposure to the cold factor in rats, a number of compensatory-adaptive reactions are activated. The decrease in the rate of Ca2+ – induced swelling and calcium capacity of mitochondria at the initial stages of hypothermia may be associated with the formation of mitochondrial pores and is reversible.