Referenced in: none

Automatically associated channels: Kv7.1 , Slo1

Title: Characterization of luminal and peritubular membrane K+ selectivity in proximal tubular cells of frog kidney.

Authors: Jelena Nesović, Dusan Cemerikic

Journal, date & volume: Ann. N. Y. Acad. Sci., 2005 Jun , 1048, 441-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16154972

Abstract
The functional significance of KCNQ1/KCNE1 K(+) secretory fluxes and the effects of 3 micromol/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.