Intracellular compartmentation of Na+, K+ and Cl- in the Ehrlich ascites tumor cell: correlation with the membrane potential.
The intracellular distribution of Na+, K+, Cl- and water has been studied in the Ehrlich ascites tumor cell. Comparison of the ion and water contents of whole cells with those of cells exposed to La3+ and mechanical stress indicated that La3+ treatment results in selective damage to the cell membrane and permits evaluation of cytoplasmic and nuclear ion concentrations. The results show that Na+ is sequestered within the nucleus, while K+ and Cl- are more highly concentrated in the cell cytoplasm. Reduction of the [Na+] of the incubation medium by replacement with K+ results in reduced cytoplasmic [Na+], increased [Cl-] and no change in [K+]. Nuclear concentrations of these ions are virtually insensitive to the cation composition of the medium. Concomitant measurements of the membrane potential were made. The potential in control cells was -13.7 mV. Reduction of [Na+] in the medium caused significant depolarization. The measured potential is describable by the Cl- equilibrium potential and can be accounted for in terms of cation distributions and permeabilities. The energetic implications of the intracellular compartmentation of ions are discussed.
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor; D002462:Cell Membrane / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured / Q000187:drug effects; D002713:Chlorine / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D007444:Inulin / Q000378:metabolism; D007811:Lanthanum / Q000494:pharmacology; D008564:Membrane Potentials; D051379:Mice; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D014867:Water / Q000378:metabolism
D014867:Water; D002713:Chlorine; D007811:Lanthanum; D007444:Inulin; D012964:Sodium; D011188:Potassium