Generation of plasma membrane potential by the Na+-pump coupled to proton extrusion |
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Authors: | C L Bashford C A Pasternak |
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Institution: | (1) Department of Biochemistry, St George's Hospital Medical School, Cranmer Terrace, SW17 ORE London, England |
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Abstract: | Lettré cells maintain a plasma membrane potential near — 60mV, 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. |
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Keywords: | Lymphocytes Lettré cells membrane potential Na+ pump cation diffusion |
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