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Characterization of Luminal and Peritubular Membrane K + Selectivity in Proximal Tubular Cells of Frog Kidney
Author(s) -
NEŠOVIĆ JELENA,
ČEMERIKIĆ DUŠAN
Publication year - 2005
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1342.059
Subject(s) - peritubular capillaries , depolarization , chemistry , medicine , membrane potential , biophysics , hyperpolarization (physics) , endocrinology , repolarization , kidney , biology , electrophysiology , stereochemistry , nuclear magnetic resonance spectroscopy
A bstract : The functional significance of/KCNQ1/KCNE1 K + secretory fluxes and the effects of 3 μmol/L Cd 2+ on the peritubular cell membrane potential and its potassium selectivity were investigated in proximal tubular cells of the frog kidney. Perfusing the lumen with l‐phenylalanine plus/minus chromanol 293B, a specific blocker of KCNQ1, did not modify rapid depolarization and rate of slow repolarization of the peritubular cell membrane. Peritubular exposure to Cd 2+ led to a sustained, reversible hyperpolarization of the peritubular membrane, paralleled by an increase in fractional K + conductance. Peritubular barium blunted hyperpolarization of the peritubular cell membrane to Cd 2+ . Thus, the KCNQ1/KCNE1 K + secretory fluxes are absent in proximal tubule of frog kidney, while Cd 2+ increases K + selectivity of the peritubular cell membrane.