Effects of anoxia and inhibitors of energy metabolism on potassium and sodium homeostasis in neurons of gastropod mollusk

Abstract

The effect of anoxia and inhibitors of energy metabolism on intracellular concentrations of potassium and sodium, membrane potentials, permeability, active and passive ouabain-sensitive transport of potassium (determined with86Rb) was studied in neurons of the freshwater planorbis mollusk (Planorbarius corneus). X-ray microanalysis showed that incubation of isolated ganglia in oxygen-free medium induced no change in intracellular concentrations of potassium and sodium. In the presence of cyanide, absorption of oxygen by the ganglia ceased, but accumulation of86Rb decreased insignificantly. The membrane potential and permeability did not depend on addition of cyanide. Desoxyglucose, an inhibitor of glycolysis, decreased86Rb accumulation more than cyanide did. In the presence of inhibitors of both glycolysis and respiration, which excluded the possibility of mutual compensation of oxidation and glycolytic sources of energy supply,86Rb accumulation decreased to the highest degree. A hypothesis was formulated on the paramount importance of glycolytic ATP for maintaining ion homeostasis of the nerve cells. The problem of functionally facilitated compartmentation of intracellular energy sources is discussed.