Document Detail

A time-resolved X-ray diffraction study of muscle during twitch.
MedLine Citation:
PMID:  307597     Owner:  NLM     Status:  MEDLINE    
1. A position sensitive X-ray counter was connected to a data-collection system which registered the outputs of the counter as a function of time. This enabled us to study time-dependent changes in the intensities of the equatorial reflexions from frog sartorius muscle during an isometric twitch. 2. The intensity ratio of the 1.0 and 1.1 equatorial reflexions (I1,0/I1,1) decreased during a twitch. The time at which the intensity ratio started to decrease coinsided approximately with the onset of tension development. No detectable change in the intensity ratio occurred during the latency relaxation. 3. The intensity ratio reached a minimum level approximately 90 msec before the peak of tension, and stayed at that level until the peak tension. 4. The intensity ratio returned to the 'resting' value 0.7--1.1 sec after the twitch tension had fallen to zero. 5. The observed decrease in the intensity ratio was interpreted as being caused by radial movements of the myosin projections from the vicinity of thick filaments to that of thin filaments. This leads us to conclude that, early in the rising phase of twitch tension, the number of myosin projections in the vicinity of thin filaments reaches the value obtained during a maximum isometric tetanus.
I Matsubara; N Yagi
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The Journal of physiology     Volume:  278     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1978 May 
Date Detail:
Created Date:  1978-09-15     Completed Date:  1978-09-15     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  297-307     Citation Subset:  IM    
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MeSH Terms
Muscle Contraction*
Rana catesbeiana
Time Factors
X-Ray Diffraction

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

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