| Exercise training corrects control of spontaneous calcium waves in hearts from myocardial infarction heart failure rats. | |
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MedLine Citation:
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PMID: 21465470 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Impaired cardiac control of intracellular diastolic Ca(2+) gives rise to arrhythmias. Whereas exercise training corrects abnormal cyclic Ca(2+) handling in heart failure, the effect on diastolic Ca(2+) remains unstudied. Here, we studied the effect of exercise training on the generation and propagation of spontaneous diastolic Ca(2+) waves in failing cardiomyocytes. Post-myocardial infarction heart failure was induced in Sprague-Dawley rats by coronary artery ligation. Echocardiography confirmed left ventricular infarctions of 40±5%, whereas heart failure was indicated by increased left ventricular end-diastolic pressures, decreased contraction-relaxation rates, and pathological hypertrophy. Spontaneous Ca(2+) waves were imaged by laser linescanning confocal microscopy (488nm excitation/505-530nm emission) in 2μM Fluo-3-loaded cardiomyocytes at 37°C and extracellular Ca(2+) of 1.2mM and 5.0mM. These studies showed that spontaneous Ca(2+) wave frequency was higher at 5.0mM than 1.2mM extracellular Ca(2+) in all rats, but failing cardiomyocytes generated 50% (p<0.01) more waves compared to sham-operated controls at Ca(2+) 1.2mM and 5.0mM. Exercise training reduced the frequency of spontaneous waves at both 1.2mM and 5.0mM Ca(2+) (p<0.05), although complete normalization was not achieved. Exercise training also increased the aborted/completed ratio of waves at 1.2mM Ca(2+) (p<0.01), but not 5.0mM. Finally, we repeated these studies after inhibiting the nitric oxide synthase with L-NAME. No differential effects were found; thus, mediation did not involve the nitric oxide synthase. In conclusion, exercise training improved the cardiomyocyte control of diastolic Ca(2+) by reducing the Ca(2+) wave frequency and by improving the ability to abort spontaneous Ca(2+) waves after their generation, but before cell-wide propagation. © 2011 Wiley Periodicals, Inc. |
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Authors:
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Ole J Kemi; Niall Macquaide; Morten A Hoydal; Oyvind Ellingsen; Godfrey L Smith; Ulrik Wisloff |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-4-4 |
Journal Detail:
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Title: Journal of cellular physiology Volume: - ISSN: 1097-4652 ISO Abbreviation: - Publication Date: 2011 Apr |
Date Detail:
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Created Date: 2011-4-5 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0050222 Medline TA: J Cell Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011 Wiley Periodicals, Inc. |
Affiliation:
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Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK. Ole.Kemi@glasgow.ac.uk. |
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