A POSSIBLE ROLE OF THE COLD-INDUCED IONIC STRESS IN THE COLD-INDUCED CELL-DEATH

Analysis of experimental results and published data within the framewo rk of the suggested mathematical model of ion-osmotic homeostasis reve aled dependance of a variety of cell parameters on temperature. It is shown that a cold-induced drastic increase in the base concentration o f cytoplasmic Ca is determined, on the one hand, by supression of the transport processes responsible for Ca removal from the cytoplasm, and , on the other hand, by increase of calcium fluxes, both from outer me dium and from cell organelles. The cold-induced variation in the ratio of permiabilities for Na and K ions was found, that can be determined by the activation of different calcium- and potential-dependant chann els or by formation of membrane flaws. Except the flow of calcium ions through appropriate selective channels, the delivery of calcium into cytosole through the membrane flaws, actively induced by cell cooling, can not be excluded. The formation of nonselective transmembrane chan nels was promoted by lipid peroxidation and proteolisis, which are ind uced by an increase in the basal concentration of calcium. The new app roaches for protecting the cell from cold injury are discussed.