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Effect of hindlimb unweighting on single soleus fiber maximal shortening velocity and ATPase activityThe effect of hindlimb unweighting (HU) for 1 to 3 wks on the shortening velocity of a soleus fiber, its ATPase content, and the relative contents of the slow and fast myosin was investigated by measuring fiber force, V(0), ATPase activity, and myosin content in SDS protein profiles of a single rat soleus fiber suspended between a motor arm and a transducer. It was found that HU induces a progressive increase in fiber V(0) that is likely caused, at least in part, by an increase in the fiber's myofibrillar ATPase activity. The HU-induced increases in V(0) and ATPase were associated with the presence of a greater percentage of fast type IIa fibers. However, a large population of fibers after 1, 2, and 3 wks of HU showed increases in V(0) and ATPase but displayed the same myosin protein profile on SDS gels as control fibers.
Document ID
19930065297
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mcdonald, K. S.
(NASA Ames Research Center Moffett Field, CA, United States)
Fitts, R. H.
(Marquette Univ. Milwaukee, WI, United States)
Date Acquired
August 16, 2013
Publication Date
June 1, 1993
Publication Information
Publication: Journal of Applied Physiology
Volume: 74
Issue: 6
ISSN: 8750-7587
Subject Category
Life Sciences (General)
Accession Number
93A49294
Funding Number(s)
CONTRACT_GRANT: NAG2-212
Distribution Limits
Public
Copyright
Other

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