| Ca2+ sensitization and PKC contribute to exercise training-enhanced contractility in porcine collateral-dependent coronary arteries. | |
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MedLine Citation:
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PMID: 21297028 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Exercise training enhances endothelium-dependent coronary vasodilatation, improving perfusion and contractile function of collateral-dependent myocardium. Paradoxically, studies from our laboratory have revealed increased Ca(2+)-dependent basal active tone in collateral-dependent arteries of exercise-trained pigs. In this study, we tested the hypothesis that exercise training enhances agonist-mediated contractile responses of collateral-dependent arteries by promoting Ca(2+) sensitization. Ameroid constrictors were surgically placed around the proximal left circumflex coronary (LCX) artery of female Yucatan miniature pigs. Eight weeks postoperatively, pigs were randomized into sedentary (pen confined) or exercise-training (treadmill run; 5 days/wk; 14 wk) groups. Arteries (∼150 μm luminal diameter) were isolated from the collateral-dependent and nonoccluded (left anterior descending artery supplied) myocardial regions, and measures of contractile tension or simultaneous tension and intracellular free Ca(2+) concentration levels (fura-2) were completed. Exercise training enhanced contractile responses to endothelin-1 in collateral-dependent compared with nonoccluded arteries, an effect that was more pronounced in the presence of nitric oxide synthase inhibition (N(ω)-nitro-l-arginine methyl ester; 100 μM). Contractile responses to endothelin-1 were not altered by coronary occlusion alone. Exercise training produced increased tension at comparable levels of intracellular free Ca(2+) concentration in collateral-dependent compared with nonoccluded arteries, indicative of exercise training-enhanced Ca(2+) sensitization. Inhibition of PKC (calphostin C; 1 μM), but not Rho-kinase (Y-27632, 10 μM; or hydroxyfasudil, 30 μM), abolished the training-enhanced endothelin-1-mediated contractile response. Exercise training also increased sensitivity to the PKC activator phorbol 12,13-dibutyrate in collateral-dependent compared with nonoccluded arteries. Taken together, these data reveal that exercise training enhances endothelin-1-mediated contractile responses in collateral-dependent coronary arteries likely via increased PKC-mediated Ca(2+) sensitization. |
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Authors:
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Juan Carlos Robles; Michael Sturek; Janet L Parker; Cristine L Heaps |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2011-02-04 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 300 ISSN: 1522-1539 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2011 Apr |
Date Detail:
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Created Date: 2011-03-31 Completed Date: 2011-06-20 Revised Date: 2012-04-02 |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H1201-9 Citation Subset: IM |
Affiliation:
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Michael E. DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, Texas A&M University, College Station, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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analogs & derivatives,
pharmacology Amides / pharmacology Animals Calcium / physiology* Collateral Circulation / drug effects, physiology Coronary Vessels / drug effects, physiology* Endothelin-1 / physiology Enzyme Inhibitors / pharmacology Female Muscle Contraction / drug effects, physiology* Naphthalenes / pharmacology Phorbol 12,13-Dibutyrate / pharmacology Physical Conditioning, Animal / physiology* Protein Kinase C / antagonists & inhibitors, physiology* Pyridines / pharmacology Swine / physiology Vasodilator Agents / pharmacology rho-Associated Kinases / antagonists & inhibitors |
| Grant Support | |
ID/Acronym/Agency:
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R01-HL-064931/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Amides; 0/Endothelin-1; 0/Enzyme Inhibitors; 0/Naphthalenes; 0/Pyridines; 0/Vasodilator Agents; 0/hydroxyfasudil; 121263-19-2/calphostin C; 138381-45-0/Y 27632; 37558-16-0/Phorbol 12,13-Dibutyrate; 7440-70-2/Calcium; 84477-87-2/1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; EC 2.7.11.1/rho-Associated Kinases; EC 2.7.11.13/Protein Kinase C |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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