Related Experiment Video
Updated: May 1, 2026
Myo-mechanical Analysis of Isolated Skeletal Muscle
Published on: February 22, 2011
Contractile properties of slow and fast skeletal muscles from protease activated receptor-1 null mice
Paran K Sitparan1, Charles N Pagel, Gavin J Pinniger
1School of Anatomy, Physiology and Human Biology, M311, The University of Western Australia, Crawley, WA, 6009, Australia.
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.
More Related Videos
08:12Author Spotlight: Isolation of Long Muscle Fibers from Mouse Hindlimb Muscles for Studying Excitation-Contraction Coupling Across Fiber Types
Published on: December 1, 2023
14:02Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
Related Concept Videos
01:25Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
01:10Muscle Contraction
01:15Muscle Contraction
01:29Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....