| Ca(2+)-activated K(+) channels of small and intermediate conductance control eNOS activation through NAD(P)H oxidase. | |
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MedLine Citation:
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PMID: 22210378 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Ca(2+)-activated K(+) channels (K(Ca)) and NO play a central role in the endothelium-dependent control of vasomotor tone. We evaluated the interaction of K(Ca) with NO production in isolated arterial mesenteric beds of the rat. In phenylephrine-contracted mesenteries, acetylcholine (ACh)-induced vasodilation was reduced by NO synthase (NOS) inhibition with N(ω)-nitro-l-arginine (L-NA), but in the presence of tetraethylammonium, L-NA did not further affect the response. In KCl-contracted mesenteries, the relaxation elicited by 100nM ACh or 1μM ionomycin was abolished by L-NA, tetraethylammonium, or simultaneous blockade of small-conductance K(Ca) (SK(Ca)) channels with apamin and intermediate-conductance K(Ca) (IK(Ca)) channels with triarylmethane-34 (TRAM-34). Apamin-TRAM-34 treatment also abolished 100nM ACh-activated NO production, which was associated with an increase in superoxide formation. Endothelial cell Ca(2+) buffering with BAPTA elicited a similar increment in superoxide. Apamin-TRAM-34 treatment increased endothelial NOS phosphorylation at threonine 495 (P-eNOS(Thr495)). Blockade of NAD(P)H oxidase with apocynin or superoxide dismutation with PEG-SOD prevented the increment in superoxide and changes in P-eNOS(Thr495) observed during apamin and TRAM-34 application. Our results indicate that blockade of SK(Ca) and IK(Ca) activates NAD(P)H oxidase-dependent superoxide formation, which leads to inhibition of NO release through P-eNOS(Thr495). These findings disclose a novel mechanism involved in the control of NO production. |
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Authors:
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Pablo S Gaete; Mauricio A Lillo; Nicolás M Ardiles; Francisco R Pérez; Xavier F Figueroa |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-12-23 |
Journal Detail:
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Title: Free radical biology & medicine Volume: - ISSN: 1873-4596 ISO Abbreviation: - Publication Date: 2011 Dec |
Date Detail:
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Created Date: 2012-1-2 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8709159 Medline TA: Free Radic Biol Med Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011 Elsevier Inc. All rights reserved. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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