Ba2+-sensitive K+ channels in luminal-membrane vesicles from pars convoluta of rabbit proximal tubule |
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Authors: | C Jacobsen H R?igaard-Petersen M I Sheikh |
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Affiliation: | Institute of Medical Biochemistry, University of Aarhus, Denmark. |
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Abstract: | This paper describes properties of 86Rb+ fluxes through a novel K+ channel in luminal-membrane vesicles isolated from pars convoluta of rabbit proximal tubule. The uptake of 86Rb+ into potassium salt loaded vesicles was specifically inhibited by Ba2+. The isotope accumulation is driven by an electrical diffusion potential as shown in experiments using these membrane vesicles loaded with anions of different membrane permeability and was as follows: gluconate greater than SO4(2-) greater than Cl-. Furthermore, the vesicles containing the channels show a cation selectivity with the order K+ greater than Rb+ greater than Li+ greater than Na+ = choline+. |
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