Ba2+-sensitive K+ channels in luminal-membrane vesicles from pars convoluta of rabbit proximal tubule.
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+.
Jacobsen
C
C
Institute of Medical Biochemistry, University of Aarhus, Denmark.
Røigaard-Petersen
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H
Sheikh
M I
MI
D000818:Animals; D000838:Anions / Q000378:metabolism; D001464:Barium / Q000494:pharmacology*; D002412:Cations / Q000494:pharmacology; D004594:Electrophysiology; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010539:Permeability; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D011817:Rabbits; D012414:Rubidium Radioisotopes
D000838:Anions; D002412:Cations; D015221:Potassium Channels; D012414:Rubidium Radioisotopes; D001464:Barium; D010042:Ouabain