Potassium accumulation by bulk prepared neuronal and glial cells.

Abstract

Abstract— Neuronal and glial cell enriched fractions were prepared by density gradient centrifugation of suspensions from rabbit cerebral cortex. The two cell types were incubated separately in media of extracellular ionic composition. The potassium accumulation was determined from analysis of potassium content of the cells by ultramicro flame photometry. Both neuronal and glial cells were capable of active potassium transport which was inhibited by ouabain (2 × 10−4m). The glial cells could accumulate potassium up to four to five times the concentration of the incubation medium and neurons up to one and a half to two times the medium concentration. The respiration in low potassium media was stimulated 15 per cent for neurons and 85 per cent for glia when potassium was added to a final concentration of 50 mm. The uptake by both neurons and glia showed temperature and sodium dependence. There was a definite magnesium requirement for the potassium uptake, particularly demonstrable for glial cells. Calcium inhibited potassium uptake by glia but stimulated slightly that by neurons.