Document Detail


Calcium sensitivity of isometric tension is increased in canine experimental heart failure.
MedLine Citation:
PMID:  7728995     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To examine the role of alterations in myofibrillar function in chronic heart failure, we determined isometric tension-pCa relations in permeabilized myocardium from a canine model of dilated cardiomyopathy (DCM) produced by chronic rapid pacing. In the initial series of experiments, seven dogs were paced at 250 beats per minute for 28.9 +/- 7.0 days, resulting in ventricular dilatation and reduced ejection fractions by echocardiography and elevated intracardiac filling pressures. Isometric tension-pCa relations were measured by using mechanically disrupted and permeabilized myocyte-sized preparations obtained from left ventricular biopsies before (n = 11) and after (n = 10) chronic rapid pacing-induced heart failure. Resting sarcomere length (SL) was set at 2.35 microns, and preparations had low end compliance (SL was 2.23 +/- 0.03 microns during maximal activation). Passive tension (2.1 +/- 1.0 versus 2.4 +/- 0.6 mN/mm2) and maximal Ca(2+)-activated tension (25.9 +/- 9.3 versus 27.8 +/- 6.8 mN/mm2) were similar for control and DCM preparations, respectively. However, the calcium sensitivity of isometric tension was increased in failing myocardium (pCa50 5.95 +/- 0.11 [DCM] versus 5.83 +/- 0.10 [control], P = .001). Treatment of myofibrillar preparations with the catalytic subunit of protein kinase A decreased calcium sensitivity of tension to a greater degree in failing preparations (shift of pCa50 from 6.04 +/- 0.06 to 5.75 +/- 0.09, n = 7) than in nonfailing preparations (5.91 +/- 0.08 to 5.74 +/- 0.07, n = 8), and isometric tension-pCa relations in the two groups were not significantly different after protein kinase A treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
M R Wolff; L F Whitesell; R L Moss
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  76     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1995 May 
Date Detail:
Created Date:  1995-05-30     Completed Date:  1995-05-30     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  781-9     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Wisconsin School of Medicine, Madison, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Agonists / pharmacology
Animals
Calcium / pharmacology*
Cardiomyopathy, Dilated / physiopathology*
Disease Models, Animal
Dogs
Echocardiography
Hemodynamics
Isometric Contraction / drug effects
Myocardial Contraction / drug effects*
Myocardium / metabolism,  pathology
Phosphorylation
Troponin / metabolism
Troponin I
Grant Support
ID/Acronym/Agency:
K08-HL02969/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Troponin; 0/Troponin I; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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