Document Detail

Exercise and suspension hypokinesia-induced alterations in mechanical properties of rat fast and slow-twitch skeletal muscles.
MedLine Citation:
PMID:  20843770     Owner:  NLM     Status:  MEDLINE    
Physical activity has a modulatory role on regulatory steps of excitation-contraction coupling (ECC) determining skeletal muscle contractility. We evaluated and compared the contractile responsiveness and caffeine-induced contractures of fast (extensor digitorum longus; EDL) and slow-twitch (soleus; SOL) muscles in suspension hypokinesia (SH) and exercised rats. After SH or low intensity exercise, EDL and SOL were isolated, twitch and tetanic contractions and caffeine (10 mM) contractures were recorded. Twitch and tetanic contractions of EDL increased by 60% in exercised rats (p <0.05) while no alteration was observed after SH. Exercise did not alter twitch and tetanic contractions of SOL, while SH depressed contractions (p <0.05). Caffeine contractures were diminished in exercised rat EDL (P <0.05). In SH-rat EDL, contractures increased in amplitude (p <0.01) with a rapid time course (p <0.05). Contractures did not change in SOL after exercise or SH. We concluded that SH and exercise exerted diverse modulatory effects on skeletal muscle contractility. Contractile improvement due to exercise was prominent in EDL. Our results suggest that the muscle-type specific adaptations are related to a change in ECC due to the differences in the regulatory steps, particularly in the intracellular Ca(2+) handling mechanisms.
M Ertunc; A Atalay; M Yildirim; R Onur
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta physiologica Hungarica     Volume:  97     ISSN:  0231-424X     ISO Abbreviation:  Acta Physiol Hung     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-16     Completed Date:  2010-10-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8309201     Medline TA:  Acta Physiol Hung     Country:  Hungary    
Other Details:
Languages:  eng     Pagination:  316-25     Citation Subset:  IM    
Hacettepe University, Department of Pharmacology, Faculty of Medicine, Sihhiye 06100 Ankara, Turkey.
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MeSH Terms
Adaptation, Physiological / physiology
Caffeine / pharmacology
Calcium / metabolism
Exercise Test
Hindlimb Suspension / physiology
Immobilization / physiology*
Muscle Contraction / drug effects,  physiology
Muscle Fibers, Fast-Twitch / physiology*
Muscle Fibers, Slow-Twitch / physiology*
Muscle, Skeletal / cytology,  physiology*
Phosphodiesterase Inhibitors / pharmacology
Physical Conditioning, Animal / physiology*
Rats, Wistar
Sarcolemma / physiology
Reg. No./Substance:
0/Phosphodiesterase Inhibitors; 58-08-2/Caffeine; 7440-70-2/Calcium

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