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Time course changes in [Ca2+]i, force, and protein content in hindlimb-suspended mouse soleus musclesBACKGROUND: Exposure to reduced gravitational forces during spaceflight is associated with significant reductions in skeletal muscle mass and strength. The purpose of this study was to test the hypothesis that increases in resting cytosolic free calcium concentration ([Ca2+]i) would precede reductions in protein content and maximal isometric tetanic force (Po) in mouse soleus muscle after initiation of hindlimb suspension. METHODS: Female ICR mice (n = 42) were hindlimb suspended for 1, 2, 3, 5, or 7 d; weight-matched mice were used as controls. Following the hindlimb suspension, the left soleus muscle was used to determine Po in vitro and the right soleus muscle was used to determine protein content and [Ca2+]i via confocal laser scanning microscopy. RESULTS: Compared with controls, [Ca2+]i was elevated by 38% at 2 d, and 117% at 7 d. Compared with controls, soleus muscle total and myofibrillar protein contents were reduced 27-29% and 30-34%, respectively, at 5-7 d after initiation of hindlimb suspension. Compared with controls, soleus muscle Po was decreased by 24% at 3 d, and 38% at 7 d. CONCLUSION: It appears that resting cytosolic Ca2+ homeostasis is disturbed soon after the initiation of hindlimb suspension, and these elevations in [Ca2+]i may play a role in initiating soleus muscle atrophy.
Document ID
20040112451
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Ingalls, C. P.
(College Station United States)
Wenke, J. C.
Armstrong, R. B.
Hamilton, S. L.
Date Acquired
August 21, 2013
Publication Date
May 1, 2001
Publication Information
Publication: Aviation, space, and environmental medicine
Volume: 72
Issue: 5
ISSN: 0095-6562
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Musculoskeletal

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