| Effects of tissue fractionation on exercise-induced alterations in SR function in rat gastrocnemius muscle. | |
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MedLine Citation:
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PMID: 8964760 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Because studies into exercise-induced alterations in sarcoplasmic reticulum (SR) Ca2+ sequestration have produced conflicting reports, we have hypothesized that the differences in SR Ca(2+)-adenosinetriphosphatase (ATPase) activity and Ca2+ uptake in SR fractions observed in different studies are due to different SR isolation techniques. To investigate this possibility, rat white and red gastrocnemius muscles from control and run animals were studied by using two conventional isolation techniques to obtain a crude microsomal fraction and an isolated SR vesicle (SRV) fraction. Indexes of CM and SRV function were compared with measurements from whole muscle homogenate. Treadmill running to exhaustion did not alter SR protein yields, percent SR extraction, or basal or Ca(2+)-ATPase purification in either fraction. Ca(2+)-activated ATPase activity was not altered by exercise in any of the fractions examined, but Ca2+ uptake was reduced in the homogenates (9.48 +/- 1.4 to 6.90 +/- 0.8 nmol . mg-1.min-1) and SRV fractions (84.0 +/- 11.5 to 50.7 +/- 14.0 nmol . mg-1.min-1) from the red gastrocnemius at free Ca2+ concentrations of 600-700 nM. These data indicate that reductions in SR Ca2+ uptake are dissociated from changes in Ca(2+)-ATPase in vitro and occur only in a specific population of vesicles. The mechanisms underlying these alterations are not known but may involve a reduction in the number of Ca(2+)-ATPase enzymes or a selective sedimentation of damaged vesicles in the SRV fraction. |
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Authors:
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E R Chin; H J Green |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 80 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1996 Mar |
Date Detail:
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Created Date: 1996-12-03 Completed Date: 1996-12-03 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 940-8 Citation Subset: IM; S |
Affiliation:
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Department of Kinesiology, University of Waterloo, Ontario, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Triphosphatases
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physiology* Animals Calcium / metabolism* Female Muscle Fatigue / physiology* Muscle, Skeletal / metabolism* Physical Conditioning, Animal / physiology* Rats Rats, Wistar Sarcoplasmic Reticulum / physiology* |
| Chemical | |
Reg. No./Substance:
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7440-70-2/Calcium; EC 3.6.1.-/Adenosine Triphosphatases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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