Document Detail


Combined in situ analysis of metabolic and myoelectrical changes associated with electrically induced fatigue.
MedLine Citation:
PMID:  12819224     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Electrical muscle stimulation (Mstim) at a low or high frequency is associated with failure of force production, but the exact mechanisms leading to fatigue in this model are still poorly understood. Using 31P magnetic resonance spectroscopy (31PMRS), we investigated the metabolic changes in rabbit tibialis anterior muscle associated with the force decline during Mstim at low (10 Hz) and high (100 Hz) frequency. We also simultaneously recorded the compound muscle mass action potential (M-wave) evoked by direct muscle stimulation, and we analyzed its post-Mstim variations. The 100-Hz Mstim elicited marked M-wave alterations and induced mild metabolic changes at the onset of stimulation followed by a paradoxical recovery of phosphocreatine (PCr) and pH during the stimulation period. On the contrary, the 10-Hz Mstim produced significant PCr consumption and intracellular acidosis with no paradoxical recovery phenomenon and no significant changes in M-wave characteristics. In addition, the force depression was linearly linked to the stimulation-induced acidosis and PCr breakdown. These results led us to conclude that force failure during 100-Hz Mstim only results from an impaired propagation of muscle action potentials with no metabolic involvement. On the contrary, fatigue induced by 10-Hz Mstim is closely associated with metabolic changes with no alteration of the membrane excitability, thereby underlining the central role of muscle energetics in force depression when muscle is stimulated at low frequency. Finally, our results further indicate a reduction of energy cost of contraction when stimulation frequency is increased from 10 to 100 Hz.
Authors:
J L Darques; D Bendahan; M Roussel; B Giannesini; F Tagliarini; Y Le Fur; P J Cozzone; Y Jammes
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Publication Detail:
Type:  Journal Article     Date:  2003-06-20
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  95     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-09-12     Completed Date:  2004-04-28     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1476-84     Citation Subset:  IM    
Affiliation:
Laboratoire de Physiopathologie Respiratoire, UPRES EA 2201, Institut Jean Roche, Faculté de Médecine, Université de la Méditerranée, Bd Pierre Dramard, 13916 Marseille Cedex 20, France. jammesyves48@aol.com
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MeSH Terms
Descriptor/Qualifier:
Acidosis / etiology
Action Potentials
Animals
Electric Stimulation / methods
Electrophysiology
Energy Metabolism
Hydrogen-Ion Concentration
Magnetic Resonance Spectroscopy
Muscle Contraction / physiology
Muscle Fatigue / physiology*
Phosphocreatine / metabolism
Phosphorus
Rabbits
Reaction Time
Chemical
Reg. No./Substance:
67-07-2/Phosphocreatine; 7723-14-0/Phosphorus

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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