Characterization of Luminal and Peritubular Membrane K+ Selectivity in Proximal Tubular Cells of Frog Kidney

: The functional significance of/KCNQ1/KCNE1 K+ secretory fluxes and the effects of 3 μmol/L Cd2+ 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 293...

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Bibliographic Details
Published in:Annals of the New York Academy of Sciences 2005-06, Vol.1048 (1), p.441-444
Main Authors: NESOVIC, JELENA, CEMERIKIC, DUSAN
Format: Article
Language:English
Subjects:
Animals
Anura
Barium - pharmacology
Blocking
cadmium
Cadmium - pharmacology
Cell Membrane Permeability - drug effects
cell membrane potential
chromanol 293B
Chromans - pharmacology
Conductance
Electrophysiology
Fluxes
frog kidney
Frogs
K+ selectivity
KCNQ Potassium Channels - drug effects
KCNQ Potassium Channels - metabolism
KCNQ1 Potassium Channel - drug effects
KCNQ1 Potassium Channel - metabolism
KCNQ1/KCNE1
Kidney - cytology
Kidney - metabolism
Kidney Tubules, Proximal - drug effects
Kidney Tubules, Proximal - metabolism
Kidneys
Lumens
Membrane Potentials - drug effects
Membrane Potentials - physiology
Membranes
Phenylalanine - pharmacology
Potassium - pharmacology
Ranidae - physiology
Selectivity
Sulfonamides - pharmacology
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Summary:: The functional significance of/KCNQ1/KCNE1 K+ secretory fluxes and the effects of 3 μmol/L Cd2+ 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 Cd2+ 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 Cd2+. Thus, the KCNQ1/KCNE1 K+ secretory fluxes are absent in proximal tubule of frog kidney, while Cd2+ increases K+ selectivity of the peritubular cell membrane.
ISSN:0077-8923
1749-6632
DOI:10.1196/annals.1342.059