Effects of carnosine on contractile apparatus Ca²⁺ sensitivity and sarcoplasmic reticulum Ca²⁺ release in human skeletal muscle fibers

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...

Full description

Saved in:
Bibliographic Details
Published in:Journal of applied physiology (1985) 2012-03, Vol.112 (5), p.728-736
Main Authors: Dutka, T L, Lamboley, C R, McKenna, M J, Murphy, R M, Lamb, G D
Format: Article
Language:English
Subjects:
Adult
Caffeine - pharmacology
Calcium - metabolism
Carnosine - pharmacology
Cytoplasm - drug effects
Cytoplasm - metabolism
Excitation Contraction Coupling - drug effects
Female
Humans
Magnesium - metabolism
Male
Muscle Contraction - drug effects
Muscle Fibers, Fast-Twitch - drug effects
Muscle Fibers, Fast-Twitch - metabolism
Muscle Fibers, Slow-Twitch - drug effects
Muscle Fibers, Slow-Twitch - metabolism
Muscle, Skeletal - drug effects
Muscle, Skeletal - metabolism
Myosin Heavy Chains - metabolism
Sarcoplasmic Reticulum - drug effects
Sarcoplasmic Reticulum - metabolism
Troponin C - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:1522-1601
DOI:10.1152/japplphysiol.01331.2011