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ID 30874
file
creator
Kanzaki, Keita
Kuratani, Mai
Mishima, Takaaki
Matsunaga, Satoshi
subject
Myosin heavy chain
Muscle damage
Stretched contraction
Proteolysis
Myofibrillar ATPase
NDC
Medical sciences
abstract
The present study investigated the effects of eccentric muscle contractions (ECC) on the content of myofibrillar proteins (my-proteins) and the catalytic activity of myofibrillar ATPase (my-ATPase) in skeletal muscles. Rat extensor digitorum longus and tibialis anterior muscles were exposed to 200-repeated ECC or isometric contractions (ISC) and used for measures of force output and for biochemical analyses, respectively. Whereas in ISC-treated muscles, full restoration of tetanic force was attained after 2 days of recovery, force developed by ECC-treated muscles remained depressed (P<0.05) after 6 days. The total my-protein content and the relative content of myosin heavy chain (MHC) in total my-proteins were unaltered during 4 days of recovery after ECC, but fell (P<0.05) to 55.9 and 63.4% after 6 days of recovery, respectively. my-ATPase activity expressed on a my-protein weight basis was unaltered immediately after ECC. However, it decreased (P<0.05) to 75.3, 45.3, and 49.3% after 2, 4 and 6 days of recovery, respectively. Total maximal calpain activity measured at 5 mM Ca2+ was significantly augmented (P<0.05) after 2 days of recovery, reaching a level of threefold higher after 6 days. These alterations were specific for ECC and not observed for ISC. These results suggest that depressions in my-ATPase activity contribute to ECC-induced decreases in force and power which can take a number of days to recover.
journal title
European Journal of Applied Physiology
volume
Volume 110
issue
Issue 5
start page
943
end page
952
date of issued
2010-11
publisher
Springer
issn
1439-6319
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) 2010 Springer
relation
The original publication is available at www.springerlink.com
relation url
department
Graduate School of Integrated Arts and Sciences



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