| Phosphocreatine recovery kinetics following low- and high-intensity exercise in human triceps surae and rat posterior hindlimb muscles. | |
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MedLine Citation:
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PMID: 18945946 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Previous studies have suggested the recovery of phosphocreatine (PCr) after exercise is at least second-order in some conditions. Possible explanations for higher-order PCr recovery kinetics include heterogeneity of oxidative capacity among skeletal muscle fibers and ATP production via glycolysis contributing to PCr resynthesis. Ten human subjects (28 +/- 3 yr; mean +/- SE) performed gated plantar flexion exercise bouts consisting of one contraction every 3 s for 90 s (low-intensity) and three contractions every 3 s for 30 s (high-intensity). In a parallel gated study, the sciatic nerve of 15 adult male Sprague-Dawley rats was electrically stimulated at 0.75 Hz for 5.7 min (low intensity) or 5 Hz for 2.1 min (high intensity) to produce isometric contractions of the posterior hindlimb muscles. [(31)P]-MRS was used to measure relative [PCr] changes, and nonnegative least-squares analysis was utilized to resolve the number and magnitude of exponential components of PCr recovery. Following low-intensity exercise, PCr recovered in a monoexponential pattern in humans, but a higher-order pattern was typically observed in rats. Following high-intensity exercise, higher-order PCr recovery kinetics were observed in both humans and rats with an initial fast component (tau < 15 s) resolved in the majority of humans (6/10) and rats (5/8). These findings suggest that heterogeneity of oxidative capacity among skeletal muscle fibers contributes to a higher-order pattern of PCr recovery in rat hindlimb muscles but not in human triceps surae muscles. In addition, the observation of a fast component following high-intensity exercise is consistent with the notion that glycolytic ATP production contributes to PCr resynthesis during the initial stage of recovery. |
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Authors:
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Sean C Forbes; Anthony T Paganini; Jill M Slade; Theodore F Towse; Ronald A Meyer |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2008-10-22 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 296 ISSN: 0363-6119 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2009 Jan |
Date Detail:
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Created Date: 2008-12-30 Completed Date: 2009-02-06 Revised Date: 2010-09-21 |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R161-70 Citation Subset: IM |
Affiliation:
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Dept. of Physiology 2201 BPS Bldg., Michigan State Univ., East Lansing, MI 48824, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Triphosphate
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metabolism Adult Animals Electric Stimulation Exercise* Female Glycolysis Hindlimb Humans Hydrogen-Ion Concentration Kinetics Least-Squares Analysis Magnetic Resonance Spectroscopy Male Models, Biological Muscle Contraction* Muscle Fibers, Skeletal / metabolism Muscle, Skeletal / innervation, metabolism* Oxidative Phosphorylation Phosphocreatine / metabolism* Phosphorus Isotopes Rats Rats, Sprague-Dawley Sciatic Nerve / physiology |
| Grant Support | |
ID/Acronym/Agency:
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R01-AR-043903/AR/NIAMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Phosphorus Isotopes; 56-65-5/Adenosine Triphosphate; 67-07-2/Phosphocreatine |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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