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Potassium channels in basolateral membrane vesicles from pars convoluta of rabbit proximal tubule
Author(s) -
Jacobsen Christian,
Blokkebak-Poulsen Jens,
Sheikh M.I.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81183-o
Subject(s) - vesicle , chemistry , biophysics , ionophore , epithelial polarity , potassium , membrane , membrane potential , ion transporter , potassium channel , choline , ion channel , biochemistry , biology , organic chemistry , receptor
The characteristics of 86 Rb + fluxes through conductive channels in basolateral‐membrane vesicles isolated from pars convoluta of rabbit proximal tubule were investigated. In KCl loaded vesicles a transient accumulation of 86 Rb + was observed which was inhibited by BaCl 2 . The accumulation was driven by an electrical diffusion potential, as shown in experiments using membrane vesicles loaded with Li 2 SO 4 and an outwardly directed Li + gradient established with a Li + ‐ionophore. The vesicles containing the channel showed a cation selectivity with the order K + = Rb + < < Li + ⩾ Na + < choline + . The 86 Rb + flux was dependent on intravesicular Ca 2+ . Increasing concentrations of Ca 2+ gradually decreased the 86 Rb + uptake.