HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 292/3/H1404    most recent 00696.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Rogers, P. A. Articles by Dick, G. M. Search for Related Content PubMed PubMed Citation Articles by Rogers, P. A. Articles by Dick, G. M.

H₂O₂ activates redox- and 4-aminopyridine-sensitive K_v channels in coronary vascular smooth muscle

¹Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana; and ²Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and ³Department of Anesthesiology, Baylor College of Medicine, Houston, Texas

Submitted 30 June 2006 ; accepted in final form 25 October 2006

Previously, we demonstrated that coronary vasodilation in response to hydrogen peroxide (H₂O₂) is attenuated by 4-aminopyridine (4-AP), an inhibitor of voltage-gated K⁺ (K_V) channels. Using whole cell patch-clamp techniques, we tested the hypothesis that H₂O₂ increases K⁺ current in coronary artery smooth muscle cells. H₂O₂ increased K⁺ current in a concentration-dependent manner (increases of 14 ± 3 and 43 ± 4% at 0 mV with 1 and 10 mM H₂O₂, respectively). H₂O₂ increased a conductance that was half-activated at –18 ± 1 mV and half-inactivated at –36 ± 2 mV. H₂O₂ increased current amplitude; however, the voltages of half activation and inactivation were not altered. Dithiothreitol, a thiol reductant, reversed the effect of H₂O₂ on K⁺ current and significantly shifted the voltage of half-activation to –10 ± 1 mV. N-ethylmaleimide, a thiol-alkylating agent, blocked the effect of H₂O₂ to increase K⁺ current. Neither tetraethylammonium (1 mM) nor iberiotoxin (100 nM), antagonists of Ca²⁺-activated K⁺ channels, blocked the effect of H₂O₂ to increase K⁺ current. In contrast, 3 mM 4-AP completely blocked the effect of H₂O₂ to increase K⁺ current. These findings lead us to conclude that H₂O₂ increases the activity of 4-AP-sensitive K_V channels. Furthermore, our data support the idea that 4-AP-sensitive K_V channels are redox sensitive and contribute to H₂O₂-induced coronary vasodilation.

reactive oxygen species; peroxides; sulfhydryl compounds; delayed-rectifier potassium channels; coronary circulation

This article has been cited by other articles:

				L. Borbouse, G. M. Dick, S. Asano, S. B. Bender, U. D. Dincer, G. A. Payne, Z. P. Neeb, I. N. Bratz, M. Sturek, and J. D. Tune Impaired function of coronary BKCa channels in metabolic syndrome Am J Physiol Heart Circ Physiol, November 1, 2009; 297(5): H1629 - H1637. [Abstract] [Full Text] [PDF]

				L. S. Kang, R. A. Reyes, and J. M. Muller-Delp Aging impairs flow-induced dilation in coronary arterioles: role of NO and H2O2 Am J Physiol Heart Circ Physiol, September 1, 2009; 297(3): H1087 - H1095. [Abstract] [Full Text] [PDF]

				A. L. Firth, D. V. Gordienko, K. H. Yuill, and S. V. Smirnov Cellular localization of mitochondria contributes to Kv channel-mediated regulation of cellular excitability in pulmonary but not mesenteric circulation Am J Physiol Lung Cell Mol Physiol, March 1, 2009; 296(3): L347 - L360. [Abstract] [Full Text] [PDF]

				A. Adebiyi, E. M. McNally, and J. H. Jaggar Sulfonylurea Receptor-Dependent and -Independent Pathways Mediate Vasodilation Induced by ATP-Sensitive K+ Channel Openers Mol. Pharmacol., September 1, 2008; 74(3): 736 - 743. [Abstract] [Full Text] [PDF]

				G. M. Dick, I. N. Bratz, L. Borbouse, G. A. Payne, U. D. Dincer, J. D. Knudson, P. A. Rogers, and J. D. Tune Voltage-dependent K+ channels regulate the duration of reactive hyperemia in the canine coronary circulation Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2371 - H2381. [Abstract] [Full Text] [PDF]

				A. Just, C. L. Whitten, and W. J. Arendshorst Reactive oxygen species participate in acute renal vasoconstrictor responses induced by ETA and ETB receptors Am J Physiol Renal Physiol, April 1, 2008; 294(4): F719 - F728. [Abstract] [Full Text] [PDF]

				S. J. Fountain, A. Cheong, J. Li, N. Y. Dondas, F. Zeng, I. C. Wood, and D. J. Beech Kv1.5 potassium channel gene regulation by Sp1 transcription factor and oxidative stress Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2719 - H2725. [Abstract] [Full Text] [PDF]