| Exercise training-enhanced, endothelium-dependent dilation mediated by altered regulation of BK(Ca) channels in collateral-dependent porcine coronary arterioles. | |
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MedLine Citation:
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PMID: 23002811 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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OBJECTIVE: Test the hypothesis that exercise training increases the contribution of large-conductance, Ca(2+) -dependent K(+) (BK(Ca) ) channels to endothelium-mediated dilation in coronary arterioles from collateral-dependent myocardial regions of chronically occluded pig hearts and may function downstream of H(2) O(2) . METHODS: An ameroid constrictor was placed around the proximal left circumflex coronary artery to induce gradual occlusion in Yucatan miniature swine. Eight weeks postoperatively, pigs were randomly assigned to sedentary or exercise training (treadmill; 14 wk) regimens. RESULTS: Exercise training significantly enhanced bradykinin-mediated dilation in collateral-dependent arterioles (~125 μm diameter) compared with sedentary pigs. The BK(Ca) -channel blocker, iberiotoxin alone or in combination with the H(2) O(2) scavenger, polyethylene glycol catalase, reversed exercise training-enhanced dilation in collateral-dependent arterioles. Iberiotoxin-sensitive whole-cell K(+) currents (i.e., BK(Ca) -channel currents) were not different between smooth muscle cells of nonoccluded and collateral-dependent arterioles of sedentary and exercise trained groups. CONCLUSIONS: These data provide evidence that BK(Ca) -channel activity contributes to exercise training-enhanced endothelium-dependent dilation in collateral-dependent coronary arterioles despite no change in smooth muscle BK(Ca) -channel current. Taken together, our findings suggest that a component of the bradykinin signaling pathway, which stimulates BK(Ca) channels, is enhanced by exercise training in collateral-dependent arterioles and suggest a potential role for H(2) O(2) as the mediator. © 2012 John Wiley & Sons Ltd. |
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Authors:
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Wei Xie; Janet L Parker; Cristine L Heaps |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-9-24 |
Journal Detail:
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Title: Microcirculation (New York, N.Y. : 1994) Volume: - ISSN: 1549-8719 ISO Abbreviation: Microcirculation Publication Date: 2012 Sep |
Date Detail:
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Created Date: 2012-9-25 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9434935 Medline TA: Microcirculation Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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© 2012 John Wiley & Sons Ltd. |
Affiliation:
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Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, 77843; Department of Systems Biology and Translational Medicine, The Texas A&M University Health Science Center, College Station, TX, 77843. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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