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ID 23280
file
creator
Mishima, Takaaki
Sakamoto, Makoto
Sugiyama, Minako
Matsunaga, Satoshi
subject
muscle fatigue
structural modification
in vitro measurement
cation regulation protein
oxidative potential
NDC
Biology
abstract
Time-dependent changes in sarcoplasmic reticulum (SR) Ca2+-handling and Na+-K+-ATPase activity, as assessed in vitro, were investigated in the superficial (GS) and deep regions (GD) of rat gastrocnemius muscles undergoing short-term (up to 30 min) electrical stimulation. There was a rapid and progressive loss of force output during the first 5 min of stimulation. For GS, significant depressions (P < 0.05) in SR Ca2+-uptake rate and Ca2+-ATPase activity were observed during only the first 1 min. No further reductions occurred with stimulation time. SR Ca2+-release rate was significantly (P < 0.05) decreased at 3 min. For GD, significant reductions (P <0.05) in Ca2+-uptake rate, Ca2+-release rate and Ca2+-ATPase activity were manifested after 3, 5 and 5 min, respectively. A decay in Na+-K+-ATPase activity was found only in 1-min stimulated GD and 30-min stimulated GS. After 30 min, the depressed functions reverted to resting levels in GD but not in GS. The alterations in any variables examined were not parallel with changes in force output. These results suggest that, at least under the conditions used in this study, in vivo disruptions in cation regulation mediated by vigorous contractile activity would be attributable primarily to events other than structural alterations to the respective proteins.
journal title
Pflügers Archiv : European Journal of Physiology
volume
Volume 456
issue
Issue 3
start page
601
end page
609
date of issued
2008-06
publisher
Springer-Verlag
issn
0031-6768
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2007 Springer-Verlag
relation
The original version is abailable at www.springerlink.com
relation is version of URL
http://dx.doi.org/10.1007/s00424-007-0427-8
department
Graduate School of Integrated Arts and Sciences
Graduate School of Biosphere Science