Contracitile properties of single-skinned skeletal muscle fibres of the extensor digitorum longus muscle of the Australian short-nosed echidna

A J Bakker; Ann L Parkinson; S I Head

doi:10.1071/ZO05011

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Contracitile properties of single-skinned skeletal muscle fibres of the extensor digitorum longus muscle of the Australian short-nosed echidna

Journal article

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Contracitile properties of single-skinned skeletal muscle fibres of the extensor digitorum longus muscle of the Australian short-nosed echidna

A J Bakker, Ann L Parkinson and S I Head

Australian Journal of Zoology, Vol.53(4), pp.237-240

2005

DOI: https://doi.org/10.1071/ZO05011

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Abstract

skeletal muscle

Short-nosed Echidna

extensor digitorum longus muscle

Eutherian mammal fast-twitch muscle fibres share similar contractile activation properties, suggesting that these properties are highly conserved in mammals. To investigate this hypothesis, we examined the contractile properties of skeletal muscle from the order Monotremata, a mammalian order that separated from eutherians 150 million years ago. The Ca2+- and Sr2+-activation properties of single mechanically skinned skeletal muscle fibres from the extensor digitorum longus (EDL) muscle of the short-nosed echidna were determined. Sigmoidal curves fitted to force response data plotted as a function of pCa (-log[Ca2+]), had a mean slope of 4.32±0.28 and a mean pCa50 and pCa10 value of 6.18±0.01 and 6.41±0.02 respectively (n = 20). The mean pSr50, pSr10 and slope values of curves fitted to the force-response data after activation with Sr2+ were 4.80±0.03, 5.29±0.07 and 2.75±0.18 respectively (n = 20). The mean pCa50-pSr50 value for the echidna EDL fibres was 1.37±0.04. In five of the echidna fibres, exposure to submaximal Ca2+ concentrations produced myofibrillar force oscillations (mean frequency, 0.13±0.01 Hz), a phenomenon found only in eutherian slow and intermediate muscle fibres. These results show that echidna EDL fibres generally have similar contractile properties to eutherian fast-twitch skeletal muscle fibres, such as those found in the EDL of the rat.

Details

Title: Contracitile properties of single-skinned skeletal muscle fibres of the extensor digitorum longus muscle of the Australian short-nosed echidna
Authors: A J Bakker (Author) - University of Western Australia
Ann L Parkinson (Author) - University of the Sunshine Coast - Faculty of Science, Health and Education
S I Head (Author) - University of New South Wales
Publication details: Australian Journal of Zoology, Vol.53(4), pp.237-240
Publisher: C S I R O Publishing
Date published: 2005
DOI: 10.1071/ZO05011
ISSN: 0004-959X
Organisation Unit: School of Health - Biomedicine; University of the Sunshine Coast, Queensland; School of Health and Sport Sciences - Legacy; School of Health and Behavioural Sciences - Legacy
Language: English
Record Identifier: 99448773802621
Output Type: Journal article

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Collaboration types: Domestic collaboration
Web Of Science research areas: Zoology

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