Hydrogen Peroxide Inhibits Gap Junctional Coupling and Modulates Intracellular Free Calcium in Cochlear Hensen Cells

Hydrogen Peroxide Inhibits Gap Junctional Coupling and Modulates Intracellular Free Calcium in... The double whole-cell patch-clamp configuration was applied to analyze gap junctional conductance (G j ) of isolated pairs of cochlear supporting Hensen cells of guinea pig under control conditions and in the presence of hydrogen peroxide (H2O2). Under control conditions, the dependence of G j on transjunctional voltage (V j ) appeared to vary between different cell pairs with a maximum value of about 40 nS at V j close to 0 mV. The voltage dependence and the maximum amplitude of G j stayed constant for at least 2 hr. Addition of H2O2 to the bath at concentrations above 0.08 mm caused a significant decrease of G j , but the membrane potential of about −30 mV was not affected. In parallel, intracellular free calcium ([Ca2+]i) was followed using fura-2. At 0.8 mm H2O2, a sustained increase of [Ca2+]i was observed, while 0.08 mm H2O2 evoked an oscillating-like behavior of [Ca2+]i. We propose that the H2O2-evoked inhibition of gap junctional coupling of Hensen cells is closely related to pathophysiological conditions such as noise- induced hearing loss, aminoglycoside-related ototoxicity and presbycusis, which are known to be associated with production of free radicals. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Hydrogen Peroxide Inhibits Gap Junctional Coupling and Modulates Intracellular Free Calcium in Cochlear Hensen Cells

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Publisher
Springer-Verlag
Copyright
Copyright © 2001 by Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232001-0014-4
Publisher site
See Article on Publisher Site

Abstract

The double whole-cell patch-clamp configuration was applied to analyze gap junctional conductance (G j ) of isolated pairs of cochlear supporting Hensen cells of guinea pig under control conditions and in the presence of hydrogen peroxide (H2O2). Under control conditions, the dependence of G j on transjunctional voltage (V j ) appeared to vary between different cell pairs with a maximum value of about 40 nS at V j close to 0 mV. The voltage dependence and the maximum amplitude of G j stayed constant for at least 2 hr. Addition of H2O2 to the bath at concentrations above 0.08 mm caused a significant decrease of G j , but the membrane potential of about −30 mV was not affected. In parallel, intracellular free calcium ([Ca2+]i) was followed using fura-2. At 0.8 mm H2O2, a sustained increase of [Ca2+]i was observed, while 0.08 mm H2O2 evoked an oscillating-like behavior of [Ca2+]i. We propose that the H2O2-evoked inhibition of gap junctional coupling of Hensen cells is closely related to pathophysiological conditions such as noise- induced hearing loss, aminoglycoside-related ototoxicity and presbycusis, which are known to be associated with production of free radicals.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Feb 1, 2001

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