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Qualitatively different cross-bridge attachments in fast and slow muscle fiber types

Galler, S, Andruchov, O, Stephenson, Gabriela and Stephenson, D. George (2009) Qualitatively different cross-bridge attachments in fast and slow muscle fiber types. Biochemical and Biophysical Research Communications, 385 (1). pp. 44-48. ISSN 0006-291X

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Contractile properties differ between skeletal, cardiac and smooth muscles as well as between various skeletal muscle fiber types. This functional diversity is thought to be mainly related to different speeds of myosin head pulling cycles, with the molecular mechanism of force generation being essentially the same. In this study, force-generating attachments of myosin heads were investigated by applying small perturbations of myosin head pulling cycles in stepwise stretch experiments on skeletal muscle fibers of different type. Slow fibers (frog tonic and rat slow-twitch) exhibited only a ‘slow-type’ of myosin head attachment over the entire activation range, while fast fibers (frog and rat fast-twitch) displayed a ‘slow-type’ of myosin head attachment at low levels of activation, and an up to 30-times faster type at high levels of activation. These observations indicate that there are qualitative differences between the mechanisms of myosin head attachment in slow and fast vertebrate skeletal muscle fibers.

Item Type: Article
Uncontrolled Keywords: ResPubID19191. myosin isoforms, muscle fiber types, mechanism of force generation, muscle mechanics, skinned fiber
Subjects: Historical > Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
Current > FOR Classification > 1116 Medical Physiology
Depositing User: VUIR
Date Deposited: 17 Oct 2011 01:23
Last Modified: 17 Oct 2011 01:23
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Citations in Scopus: 2 - View on Scopus

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