Abstract
© 2014 Wiley Periodicals, Inc. 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.
Original language | English |
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Pages (from-to) | 991-998 |
Journal | Muscle and Nerve |
Volume | 50 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2014 |