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Oxidative Medicine and Cellular Longevity
Volume 2012, Article ID 105820, 7 pages
http://dx.doi.org/10.1155/2012/105820
Research Article

Reversible Oxidation of Myometrial Voltage-Gated Potassium Channels with Hydrogen Peroxide

1Department of Physiology, Institute for Biological Research “Sinisa Stankovic,” University of Belgrade, 11000 Belgrade, Serbia
2Faculty of Biology, University of Belgrade, 11000 Belgrade, Serbia
3Faculty of Medicine, University of Eastern Sarajevo, 73300 Foca, Bosnia and Herzegovina

Received 18 April 2012; Accepted 8 August 2012

Academic Editor: David R. Jones

Copyright © 2012 Isabella Appiah et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The uteri, spontaneously active or Ca2+ (6 mM) induced, were allowed to equilibrate, and to inhibit voltage-gated potassium ( ) channels 1 mM 4-amino pyridine (4-AP) was applied for 15 min before adding H2O2 .  H2O2 was added cumulatively: 2 μM, 20 μM, 200 μM, 400 μM, and 3 mM. Average time for H2O2 concentrations (2, 20, 200, and 400) μM to reach its full effect was 15 min. H2O2 3 mM had a prolonged effect and therefore was left to act for 30 min. Two-way ANOVA showed significant differences in time dependency between spontaneous and Ca2+-induced rat uteri after applying 3 mM H2O2 (type of contraction, ), but not 400 μM H2O2 ( ). Our results indicate that H2O2 oxidises channel intracellular thiol groups and activates the channel, inducing relaxation. Cell antioxidative defence system quickly activates glutathione peroxidase (GSHPx) defence mechanism but not catalase (CAT) defence mechanism. Intracellular redox mechanisms repair the oxidised sites and again establish deactivation of channels, recuperating contractility. In conclusion, our results demonstrate that channels can be altered in a time-dependent manner by reversible redox-dependent intracellular alterations.