Effects of temperature on cellular ion regulation and membrane transport systems

COSSINS AR, SCHWARZBAUM PJ, WIESER W

Biochemistry and Molecular Biology of fishes

Elsevier

Año: 1995; p. 101 - 126

The preservation of ionic balance, despite the direct effects of temperature upon metabolism, is of critical importance to the cells of poikilothermic animals. Because temperature differentially affects the transport mechanisms involved in ion balance, changes in the body temperature of poikilothermic animals, such as fish, may disturb the normal cellular steady state. Cells can respond adaptively to this thermal disturbance by adjustments to the transporting apparatus but these responses may be complex and do not necessarily lead to the maintenance of the status quo ante in respect of cell volume, ion balance or the associated energetic costs. From the animals point of view the most appropriate result is one that takes account of the adaptive needs of the animal in relation to the provision of a positive energy balance as well as of maintained physiological performance. When energy intake is limited, during the winter or during periods of enforced inactivity, then cellular pump activity may be reduced thereby lowering transmembrane ion gradients. This chapter discusses the strategies that animal cells might follow and the circumstances under which they would be adaptive. It then discusses the potential mechanisms by which the individual transport systems are adjusted and the evidence in favor of them.