Document Detail

Myocardial infarction alters myofilament calcium sensitivity and mechanical behavior of myocytes.
MedLine Citation:
PMID:  9038957     Owner:  NLM     Status:  MEDLINE    
To determine whether myocardial infarction leads to alterations in myofilament isometric tension as a function of Ca2+ concentration, unloaded shortening velocity, and sarcomere compliance, these properties were examined in skinned myocytes 7 days after coronary artery occlusion. Changes in myofilament proteins were also evaluated Myocardial infarction was characterized by a 10-15% reduction in myofilament isometric tension at submaximum Ca2+ levels in the physiological range. However, developed tension at maximum activation was unaltered. Conversely, unloaded shortening velocity was decreased by 31% in the remaining viable cells, whereas resting tension was increased by 30-40%. The regulatory protein troponin I content was reduced, but phosphorylation of troponin I and troponin T was increased. Myosin isoenzymes and troponin T contents were not altered. In conclusion, molecular responses occurred acutely after myocardial infarction, and these adaptations may depress the mechanical behavior of the unaffected cells, contributing to acute impairment in global cardiac pump function beyond that resulting from myocyte loss.
P Li; P A Hofmann; B Li; A Malhotra; W Cheng; E H Sonnenblick; L G Meggs; P Anversa
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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:  The American journal of physiology     Volume:  272     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Jan 
Date Detail:
Created Date:  1997-03-31     Completed Date:  1997-03-31     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H360-70     Citation Subset:  IM    
Department of Medicine, New York Medical College, Valhalla 10595, USA.
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MeSH Terms
Calcium / physiology*
Microfilaments / physiology*
Myocardial Contraction
Myocardial Infarction / pathology,  physiopathology*
Myocardium / pathology*
Rats, Sprague-Dawley
Time Factors
Troponin / metabolism
Ventricular Function*
Grant Support
Reg. No./Substance:
0/Troponin; 7440-70-2/Calcium

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

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