Document Detail


Stiffness and shortening changes in myofilament-extracted rat cardiac myocytes.
MedLine Citation:
PMID:  2916687     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Sarcomere lengths, cell widths, volumes, stiffness, and regional striation uniformity were determined from isolated adult cardiac myocytes. Single cells were examined in the control saline solution followed by a sequence of relaxing, membrane skinning, and myofilament extraction solutions. Cell size and shape parameters were determined from freely dispersed myocytes, whereas stiffness was measured from myocytes attached to a perturbator and tension transducer with micropipettes. There were small changes in cell appearance, size, shape, and stiffness in the relaxing and skinning solutions. However, in 0.17-0.56 M KCl myosin extraction media, cell length declined significantly to 1.19 microns, and stiffness fell to 5-10% of control. The rate of cell shortening and stiffness decline was dependent on KCl concentration and pH. Subsequent exposure to higher ionic strength 0.60 M KI thin filament extraction media elicited additional decreases in stiffness (less than 5% of control) and cell length (0.98 micron). Cell shortening and stiffness decline have similar time courses under the same conditions, and they appear to coincide with A-band disassembly as indicated by electron micrographs. These data suggest that cardiac myocyte stiffness, size, and shape are determined in part by a stressed cytoskeleton that is associated with the myofilament apparatus.
Authors:
K P Roos; A J Brady
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Publication Detail:
Type:  In Vitro; 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:  256     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Feb 
Date Detail:
Created Date:  1989-03-23     Completed Date:  1989-03-23     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H539-51     Citation Subset:  IM    
Affiliation:
Department of Physiology, School of Medicine, University of California, Los Angeles 90024-1760.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cytoskeleton / physiology*
Heart / physiology*
Microfilaments / drug effects,  physiology*,  ultrastructure
Microscopy, Electron
Myocardial Contraction*
Myofibrils / physiology*
Myosins / analysis,  physiology
Potassium Chloride / pharmacology
Rats
Sarcomeres / drug effects,  physiology*,  ultrastructure
Grant Support
ID/Acronym/Agency:
HL-29671/HL/NHLBI NIH HHS; HL-30828/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
7447-40-7/Potassium Chloride; EC 3.6.4.1/Myosins

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


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