title: Epigallocatechin-3-gallate protects Na+ channels in rat ventricular myocytes against sulfite.
abstract: Sulfite (bisulfite/sulfite) can affect voltage-gated sodium (Na(+)) channels (VGSC) in a concentration-dependent manner in isolated rat ventricular myocytes. In this study, the effect of epigallocatechin-3-gallate (EGCG) on VGSC in isolated ventricular myocytes was studied. Ventricular myocytes were exposed to 10 microM bisulfite/sulfite for 10 min, and EGCG was then administered in different concentrations (10, 30, 50 microg ml(-1)). Decreased activity of superoxide dismutase, catalase (CAT) and glutathione peroxidase (GPx) was observed after bisulfite/sulfite exposure, with significant increase in Na(+) currents (I (Na)) and alterations in half-activation voltage and half-inactivation voltage. Intracellular reactive oxygen species (ROS) such as hydrogen peroxide (H(2)O(2)), hydroxyl (OH(.)), and superoxide anion (O (2) (.-) ) were increased. After EGCG treatment, activity of the aforementioned enzymes increased while the ROS level decreased. The effects progressed with increasing amounts of EGCG, up to a level similar to blank control at the dose of 50 microg ml(-1) EGCG, EGCG also reduced the I (Na) and reversed the alterations in half-activation voltage and half-inactivation voltage. In conclusion, EGCG could protect Na(+) channels in rat ventricular myocytes against the oxidative damage induced by sulfite as a scavenger of the ROS.
authors.affiliation: College of Environmental Science and Resources, Shanxi University, Taiyuan, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Wei
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Meng
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002469:Cell Separation; D004594:Electrophysiology; D005979:Glutathione Peroxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology; D018384:Oxidative Stress / Q000187:drug effects; D018408:Patch-Clamp Techniques; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects*; D013447:Sulfites / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D015222:Sodium Channels; D013447:Sulfites; D013481:Superoxides; D017665:Hydroxyl Radical; D002392:Catechin; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase