title: Relationship between membrane potential and external potassium in human glioblastoma cells in tissue culture.
abstract: Cells from a human glioblastoma (TC 526) maintained in tissue culture for ten years had a mean membrane potential of 27 +/- 0.9 mV at an external potassium concentration [Ko] of 5.3 mM. When [Ko] was varied between 2.5 and 5.3 mM, membrane potential changes were close to those predicted by the Nernst equation. At higher [Ko], the Nernstian slope was approached only in the presence of 10(-5) M ouabain, which did not affect membrane potential at a [Ko] of 5.3 mM. An electrogenic sodium pump activated by high [Ko] could explain these findings; such a mechanism has been demonstrated in other tissues.
mesh_terms: D001693:Biological Transport, Active; D002460:Cell Line; D002462:Cell Membrane / Q000648:ultrastructure; D008564:Membrane Potentials / Q000187:drug effects*; D008870:Microtubules / Q000648:ultrastructure; D009457:Neuroglia / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D012270:Ribosomes / Q000648:ultrastructure; D012964:Sodium / Q000378:metabolism
chemical_list: D010042:Ouabain; D012964:Sodium; D011188:Potassium