Document Detail

Effects of carnosine on contractile apparatus Ca²⁺ sensitivity and sarcoplasmic reticulum Ca²⁺ release in human skeletal muscle fibers.
MedLine Citation:
PMID:  22174397     Owner:  NLM     Status:  MEDLINE    
There is considerable interest in potential ergogenic and therapeutic effects of increasing skeletal muscle carnosine content, although its effects on excitation-contraction (EC) coupling in human muscle have not been defined. Consequently, we sought to characterize what effects carnosine, at levels attained by supplementation, has on human muscle fiber function, using a preparation with all key EC coupling proteins in their in situ positions. Fiber segments, obtained from vastus lateralis muscle of human subjects by needle biopsy, were mechanically skinned, and their Ca(2+) release and contractile apparatus properties were characterized. Ca(2+) sensitivity of the contractile apparatus was significantly increased by 8 and 16 mM carnosine (increase in pCa(50) of 0.073 ± 0.007 and 0.116 ± 0.006 pCa units, respectively, in six type I fibers, and 0.063 ± 0.018 and 0.103 ± 0.013 pCa units, respectively, in five type II fibers). Caffeine-induced force responses were potentiated by 8 mM carnosine in both type I and II fibers, with the potentiation in type II fibers being entirely explicable by the increase in Ca(2+) sensitivity of the contractile apparatus caused by carnosine. However, the potentiation of caffeine-induced responses caused by carnosine in type I fibers was beyond that expected from the associated increase in Ca(2+) sensitivity of the contractile apparatus and suggestive of increased Ca(2+)-induced Ca(2+) release. Thus increasing muscle carnosine content likely confers benefits to muscle performance in both fiber types by increasing the Ca(2+) sensitivity of the contractile apparatus and possibly also by aiding Ca(2+) release in type I fibers, helping to lessen or slow the decline in muscle performance during fatiguing stimulation.
T L Dutka; C R Lamboley; M J McKenna; R M Murphy; G D Lamb
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-12-15
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  112     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-03-02     Completed Date:  2012-09-11     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:  728-36     Citation Subset:  IM    
Dept. of Zoology, La Trobe Univ., Melbourne 3086, Victoria, Australia.
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MeSH Terms
Caffeine / pharmacology
Calcium / metabolism*
Carnosine / pharmacology*
Cytoplasm / drug effects,  metabolism
Excitation Contraction Coupling / drug effects
Magnesium / metabolism
Muscle Contraction / drug effects*
Muscle Fibers, Fast-Twitch / drug effects*,  metabolism
Muscle Fibers, Slow-Twitch / drug effects*,  metabolism
Muscle, Skeletal / drug effects*,  metabolism
Myosin Heavy Chains / metabolism
Sarcoplasmic Reticulum / drug effects*,  metabolism
Troponin C / metabolism
Reg. No./Substance:
0/Myosin Heavy Chains; 0/Troponin C; 305-84-0/Carnosine; 58-08-2/Caffeine; 7439-95-4/Magnesium; 7440-70-2/Calcium

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