The energetic cost of activation in mouse fast-twitch muscle is the same whether measured using reduced filament overlap or N-benzyl-p-toluenesulphonamide

Barclay, CJ, Lichtwark, GA and Curtin, NA (2008) The energetic cost of activation in mouse fast-twitch muscle is the same whether measured using reduced filament overlap or N-benzyl-p-toluenesulphonamide. Acta Physiologica, 193 4: 381-391. doi:10.1111/j.1748-1716.2008.01855.x


Author Barclay, CJ
Lichtwark, GA
Curtin, NA
Title The energetic cost of activation in mouse fast-twitch muscle is the same whether measured using reduced filament overlap or N-benzyl-p-toluenesulphonamide
Journal name Acta Physiologica   Check publisher's open access policy
ISSN 1748-1708
Publication date 2008-08
Sub-type Article (original research)
DOI 10.1111/j.1748-1716.2008.01855.x
Volume 193
Issue 4
Start page 381
End page 391
Total pages 11
Editor Henriksson, J
Place of publication Oxford , U.K.
Publisher Blackwell Publishing for the Scandinavian Physiological Society
Language eng
Subject 1106 Human Movement and Sports Science
Abstract Aim: Force generation and transmembrane ion pumping account for the majority of energy expended by contracting skeletal muscles. Energy turnover for ion pumping, activation energy turnover (EA), can be determined by measuring the energy turnover when force generation has been inhibited. Most measurements show that activation accounts for 25–40% of isometric energy turnover. It was recently reported that when force generation in mouse fast-twitch muscle was inhibited using N-benzyl-p-toluenesulphonamide (BTS), activation accounted for as much as 80% of total energy turnover during submaximal contractions. The purpose of this study was to compare EA measured by inhibiting force generation by: (1) the conventional method of reducing contractile filament overlap; and (2) pharmacological inhibition using BTS. Methods: Experiments were performed in vitro using bundles of fibres from mouse fast-twitch extensor digitorum longus (EDL) muscle. Energy turnover was quantified by measuring the heat produced during 1-s maximal and submaximal tetanic contractions at 20 and 30 °C. Results: E A measured using reduced filament overlap was 0.36 ± 0.04 (n = 8) at 20 °C and 0.31 ± 0.05 (n = 6) at 30 °C. The corresponding values measured using BTS in maximal contractions were 0.46 ± 0.06 and 0.38 ± 0.06 (n = 6 in both cases). There were no significant differences among these values. EA was also no different when measured using BTS in submaximal contractions. Conclusion: Activation energy turnover is the same whether measured using BTS or reduced filament overlap and accounts for slightly more than one-third of isometric energy turnover in mouse EDL muscle.
Keyword activation
Ca2+ cycling
mouse fast-twitch muscle
muscle energy use
muscle heat production
LIGHT-CHAIN PHOSPHORYLATION
EXTENSOR DIGITORUM LONGUS
SKELETAL-MUSCLE
SLOW-TWITCH
2,3-BUTANEDIONE MONOXIME
MAMMALIAN SKELETAL
HEAT-PRODUCTION
CONTRACTILE ACTIVATION
ISOMETRIC CONTRACTION
PAPILLARY-MUSCLE
Q-Index Code C1
Q-Index Status Provisional Code

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Human Movement and Nutrition Sciences Publications
 
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Created: Tue, 15 Jun 2010, 12:00:24 EST