HYdrogen peroxide activates k+ channels in llc-pk1 cells

Dragana M. Filipovic, William B Reeves

Research output: Contribution to journalArticle

Abstract

Oxidant-induced damage has been implicated in the pathogenesis of several forms of cellular injury. The activation of K+ channels appears to be an early event in injury of renal tubular epithelial cells (Reeves and Shah, J. Clin. Invest. 94: 2289-2294, 1994). The present studies employed patch clamp methods to determine if oxidant stress leads to activation of plasma membrane K+ channels in the renal epithelial LLCPKi cell line. Cellular membrane potential was measured with the perforated whole cell current-clamp recording configuration. Exposure of these cells to H2U2 (0.1 mM to 5 mM) induced a rapid, dose-dependent membrane hyperpolarization. Whole cell voltage-clamp studies were performed to determine the ion selectivity of the currents underlying this H2U2-induced cellular hyperpolarization. H2U2 (5 mM) increased the whole cell current response to a 60 mV depolarizing pulse from 12.3 ± 1.6 pA/pF to 68.3 ±6.6 pA/pF (n = 5). In solutions where EK = -82 mV and ECI = 0 mV, the reversal potential of the H2U2-induced current was approximately -75 mV, consistent with a K+ selective conductance. This current was inhibited largely (84 ±9%) by barium (5 mM) and glibenclamide (500 |iM), but only partially by tetraethylamonium (15 mM). Single-channel studies revealed two types of Ca-independent, Kselective channels in the H202-treated cells: a 40-pS short-open time (5.3 ± 1.2 ms) channel (n =7). and a 20-pS long-open time (60 ±8 ms) channel (n =5). These findings indicate that H22 activates a Caindependent K+ conductance in LLC-PKi cells. This activation may have a role in the pathogenesis of oxidant-induced cell injury. Supported by the American Heart Association.

Original languageEnglish (US)
JournalFASEB Journal
Volume10
Issue number3
StatePublished - Dec 1 1996
Externally publishedYes

Fingerprint

Clamping devices
Oxidants
Hydrogen Peroxide
Chemical activation
Membranes
Glyburide
Induced currents
Barium
Cell membranes
Cells
Wounds and Injuries
Ions
Epithelial Cells
Kidney
Electric potential
Ion Channels
Membrane Potentials
Cell Membrane
Cell Line

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

Cite this

HYdrogen peroxide activates k+ channels in llc-pk1 cells. / Filipovic, Dragana M.; Reeves, William B.

In: FASEB Journal, Vol. 10, No. 3, 01.12.1996.

Research output: Contribution to journalArticle

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