Document Detail


Cross-bridge kinetics in fatigued mouse diaphragm.
MedLine Citation:
PMID:  10414404     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to determine cross-bridge number and kinetics in the diaphragm during fatigue and early recovery. Experiments were conducted in isolated mouse diaphragm (n=10). The force of a single cross-bridge (pi), the number of cross-bridges (m x 10(9) x mm2), the time cycle (tc) and the rate constants for cross-bridge attachment (f1) and detachment (g2) were calculated from the equations of A.F. Huxley. Following the fatigue protocol, peak isometric tension (Po) and maximum unloaded shortening velocity fell by 40+/-1% and 17+/-2%, respectively. In fatigued diaphragm, m fell by approximately 40% and returned to baseline after 10 min. When compared to baseline, g2 fell in fatigued diaphragm and remained significantly lower during the 15-min recovery period. In contrast, fatigue did not significantly modify pi, f1, or tc. There was a strong linear relationship between Po and m (p<0.001, r=0.988). No relationship was observed between tc and g2. These results indicate that changes in tension during fatigue and recovery run parallel to changes in the number of active cross-bridges, with no change in the force generated per cross-bridge. It is conceivable that fatigue durably impairs adenosine diphosphate release from the actomyosin complex without modifying the total duration of the cross-bridge cycle.
Authors:
C Coirault; P Attal; F X Blanc; D Chemla; Y Lecarpentier
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The European respiratory journal     Volume:  13     ISSN:  0903-1936     ISO Abbreviation:  Eur. Respir. J.     Publication Date:  1999 May 
Date Detail:
Created Date:  1999-09-03     Completed Date:  1999-09-03     Revised Date:  2013-05-23    
Medline Journal Info:
Nlm Unique ID:  8803460     Medline TA:  Eur Respir J     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  1055-61     Citation Subset:  IM    
Affiliation:
INSERM 451-Laboratoire d'Optique Appliquée-Ecole Polytechnique, Palaiseau, France.
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MeSH Terms
Descriptor/Qualifier:
Actomyosin / metabolism
Adenosine Diphosphate / metabolism
Animals
Diaphragm / metabolism,  physiology*
Isometric Contraction / physiology
Male
Mice
Muscle Fatigue / physiology*
Respiratory Mechanics / physiology
Time Factors
Chemical
Reg. No./Substance:
58-64-0/Adenosine Diphosphate; 9013-26-7/Actomyosin

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


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