| Exercise training increases inwardly rectifying K+ current and augments K+-mediated vasodilation in deep femoral artery of rats. | |
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MedLine Citation:
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PMID: 21349874 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Aims: A moderate increase in extracellular [K(+)] ([K(+)](e)) induces relaxation of small arteries via activating inwardly rectifying K(+) current (I(Kir)). The K(+)-vasodilation is an important mechanism for exercise-induced hyperemia in skeletal muscle. We investigated whether I(Kir) and K(+)-vasodilation are enhanced in deep femoral arteries (DFA) from exercise-trained rats (ET-rats, treadmill-running: 20 min at 20 m/min, six days for two weeks). The effects of ET on K(+)-vasodilation and I(Kir) were also investigated in cerebral (CA) and mesenteric arteries. Methods and Results: The K(+)-vasodilation of DFA and the density of I(Kir) and voltage-gated K(+) current (I(Kv)) were increased in DFA myocytes of ET-rats. The myogenic tone of DFA was unchanged by exercise. Although similar functional up-regulations of I(Kir) and I(Kv) were observed in CA myocytes, the K(+)-vasodilation was not increased in CA of ET-rats. Interestingly, concomitant to the increases in I(Kir) and I(Kv), background Na(+) conductance was also increased in the CA myocytes. However, such an effect was not observed in DFA myocytes from ET-rats. Neither I(Kir) nor K(+)-vasodilation was observed in mesenteric arteries of ET-rats. Conclusion: The present study provides evidence to report that regular exercise up-regulates I(Kir) in DFA and CA myocytes. Although the increase in I(Kir) was similarly observed in two types of arteries, augmentation of K(+)-relaxation was observed only in DFA of ET-rats, possibly due to the increased Na(+) conductance in CA myocytes. The increases in I(Kir) and K(+)-vasodilation of the arteries of skeletal muscle suggest novel mechanisms of improved exercise hyperemia with physical training. |
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Authors:
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Chun Zi Jin; Hyang Sun Kim; Eun Yeong Seo; Dong Hoon Shin; Kyung Sun Park; Yang-Sook Chun; Yin Hua Zhang; Sung Joon Kim |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-2-23 |
Journal Detail:
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Title: Cardiovascular research Volume: - ISSN: 1755-3245 ISO Abbreviation: - Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2011-2-25 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0077427 Medline TA: Cardiovasc Res Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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