| Effect of cardiac myosin binding protein-C on mechanoenergetics in mouse myocardium. | |
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MedLine Citation:
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PMID: 15155526 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We examined the effect of cardiac myosin binding protein-C (cMyBP-C) on contractile efficiency in isovolumically contracting left ventricle (LV) and on internal viscosity and oscillatory work production in skinned myocardial strips. A 6-week diet of 0.15% 6-n-propyl-2-thiouracil (PTU) was fed to wild-type (+/+(PTU)) and homozygous-truncated cMyBP-C (t/t(PTU)) mice starting at age approximately 8 weeks and leading to a myosin heavy chain (MHC) isoform profile of 10% alpha-MHC and 90% beta-MHC in both groups. Western blot analysis confirmed that cMyBP-C was present in the +/+(PTU) and effectively absent in the t/t(PTU). Total LV mechanical energy per beat was quantified as pressure-volume area (PVA). O2 consumption (Vo2) per beat was plotted against PVA at varying LV volumes. The reciprocal of the slope of the linear Vo2-PVA relation represents the contractile efficiency of converting O2 to mechanical energy. Contractile efficiency was significantly enhanced in t/t(PTU) (26.1+/-2.6%) compared with +/+(PTU) (17.1+/-1.6%). In skinned myocardial strips, maximum isometric tension was similar in t/t(PTU) (18.7+/-2.1 mN x mm(-2)) and +/+(PTU) (21.9+/-4.0 mN x mm(-2)), but maximum oscillatory work induced by sinusoidal length perturbations occurred at higher frequencies in t/t(PTU) (7.31+/-1.17 Hz) compared with +/+(PTU) (4.48+/-0.60 Hz) and was significantly more sensitive to phosphate concentration in the t/t(PTU). Under rigor conditions, the internal viscous load was significantly lower in the t/t(PTU) compared with +/+(PTU), ie, approximately 40% lower at 1 Hz. These results collectively suggest that contractile efficiency is enhanced in the t/t(PTU), probably through a reduced loss of mechanical energy by a viscous load normally provided by cMyBP-C and through a gain of phosphate-dependent oscillatory work normally inhibited by cMyBP-C. |
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Authors:
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Bradley M Palmer; Teruo Noguchi; Yuan Wang; John R Heim; Norman R Alpert; Patrick G Burgon; Christine E Seidman; J G Seidman; David W Maughan; Martin M LeWinter |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S. Date: 2004-05-20 |
Journal Detail:
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Title: Circulation research Volume: 94 ISSN: 1524-4571 ISO Abbreviation: Circ. Res. Publication Date: 2004 Jun |
Date Detail:
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Created Date: 2004-06-25 Completed Date: 2004-12-20 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0047103 Medline TA: Circ Res Country: United States |
Other Details:
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Languages: eng Pagination: 1615-22 Citation Subset: IM |
Affiliation:
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Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, University of Vermont, Burlington, Vt 05405, USA. palmer@physiology.med.uvm.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Actomyosin
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physiology Animals Biomechanics Calcium Signaling Carrier Proteins / genetics, physiology* Elasticity Energy Metabolism Female Isometric Contraction Male Mice Mice, Knockout Microfilaments / physiology, ultrastructure Myocardial Contraction / physiology* Myosin Heavy Chains / physiology Oxygen Consumption Phosphates / physiology Propylthiouracil / toxicity Systole Ventricular Function Viscosity |
| Grant Support | |
ID/Acronym/Agency:
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HL52087/HL/NHLBI NIH HHS; HL59408/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Carrier Proteins; 0/Myosin Heavy Chains; 0/Phosphates; 0/myosin-binding protein C; 51-52-5/Propylthiouracil; 9013-26-7/Actomyosin |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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