Plasma Membrane Potential of Animal Cells Generated by Ion Pumping, Not by Ion Gradients
The plasma membrane potential of animal cells is generally thought to be generated predominantly by the diffusion of K+ out of cells (Williams, 1970), with only very minor contributions from the diffusion of other ions or from an electrogenic Na+ pump (Thomas, 1972; Lew et al., 1979). The experiments to be described show that this view is no longer universally applicable, and that plasma membrane potential of at least two cell types, — a mouse tumour cell and human neutrophils, — arises predominantly from electrogenic pumping of Na+ and, to a lesser extent, of H+. In such cells electrical and osmotic stability are preserved by the operation of anion leak and electroneutral ion transport pathways (Bashford & Pasternak, 1984, 1985a,b).
KeywordsMembrane Potential Null Point Sendai Virus Plasma Membrane Potential Endocytic Vesicle
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