Uptake of Potassium at Low Temperatures in Kidney Cortex Slices of Hibernating Mammals

Abstract

IN hibernating hamsters and ground squirrels cationic concentration gradients between tissue cells and plasma are undiminished^1,2. This fact probably accounts for the ability of the excitable tissues of these species to retain high resting potentials³, to conduct action potentials^3–5 and to regulate fibre water content⁶ at the exceptionally low body temperatures of hibernation. In most mammalian tissues at normal, high body temperature the maintenance of cationic gradients across cell membranes is an active process requiring the expenditure of metabolic energy by mechanisms which transport cations against electrochemical gradients in the face of passive leaks. The question arises whether gradients continue to exist during hibernation because these mechanisms still function or because membranes are less permeable to ions at low temperature.