Strophanthidin-Sensitive Transport of Cesium and Sodium in Muscle Cells
R. A. Sjodin 1 and
L. A. Beaugé 1
1 Department of Biophysics, University of Maryland School of Medicine, Baltimore
Uptake of cesium-134 ions into muscle cells is reduced to very low values by the presence of 10-5M strophanthidin in the Ringer solution. Cesium ions can induce extrusion of sodium from muscle cells in which the intracellular sodium content is elevated. The cesium-induced extra efflux of sodium-22 is inhibited by the external presence of 10-5M strophanthidin. The coupling between inward movement of cesium and outward movement of sodium appears to be chemical in nature. The evidence suggests that cesium ions are transported into muscle cells by a system of sites or carriers that requires a source of metabolic energy for ion turnover to occur.