Generation of plasma membrane potential by the Na+-pump coupled to proton extrusion.
Lettré cells maintain a plasma membrane potential near -60 mV, yet are scarcely depolarized by 80 mM Rb+ and are relatively impermeable to 86Rb+. They are depolarized by ouabain without a concomitant change in intracellular cation content. Addition of K+ to cells suspended in a K+ free medium, or of Na+ to cells in a Na+ free medium, hyperpolarizes the cells. They contain electroneutral transport mechanisms for Na+, K+ and H+ which can function as Na+:K+ and Na+:H+ exchanges. It is concluded that plasma membrane potential of Lettré cells, in steady-state for Na+ and K+, is produced by an electrogenic Na+ pump sustained by electroneutral exchanges, and restricted by anion leakage.
Bashford
C L
CL
Pasternak
C A
CA
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000503:physiopathology; D002462:Cell Membrane / Q000502:physiology*; D002463:Cell Membrane Permeability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008214:Lymphocytes / Q000502:physiology; D008564:Membrane Potentials; D051379:Mice; D008954:Models, Biological; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*
D007473:Ion Channels; D012964:Sodium; D012413:Rubidium