The equipment used in this study was funded by a grant from the Rebecca L Cooper Medical Research Foundation.
Contractile properties of slow and fast skeletal muscles from protease activated receptor-1 null mice
Article first published online: 30 OCT 2014
© 2014 Wiley Periodicals, Inc.
Muscle & Nerve
Volume 50, Issue 6, pages 991–998, December 2014
How to Cite
Sitparan, P. K., Pagel, C. N., Pinniger, G. J., Yoo, H.J., Mackie, E. J. and Bakker, A. J. (2014), Contractile properties of slow and fast skeletal muscles from protease activated receptor-1 null mice. Muscle Nerve, 50: 991–998. doi: 10.1002/mus.24256
- Issue published online: 21 NOV 2014
- Article first published online: 30 OCT 2014
- Accepted manuscript online: 1 APR 2014 05:21AM EST
- Manuscript Accepted: 26 MAR 2014
- primary fibers;
- secondary fibers;
Introduction: Protease-activated receptors (PARs) may play a role in skeletal muscle development. We compared the contractile properties of slow-twitch soleus muscles and fast-twitch extensor digitorum longus (EDL) muscles from PAR-1 null and littermate control mice. Methods: Contractile function was measured using a force transducer system. Fiber type proportions were determined using immunohistochemistry. Results: Soleus muscles from PAR-1 null mice exhibited longer contraction times, a leftward shift in the force–stimulation frequency relationship, and decreased fatiguability compared with controls. PAR-1 null soleus muscles also had increased type 1 and decreased type IIb/x fiber numbers compared with controls. In PAR-1 null EDL muscles, no differences were found, except for a slower rate of fatigue compared with controls. Conclusions: The absence of PAR-1 results in a slower skeletal muscle contractile phenotype, likely due to an increase in type I and a decrease in type IIb/x fiber numbers. Muscle Nerve 50: 991–998, 2014