The Contractile Phenotype of Skeletal Muscle in TRPV1 Knockout Mice is Gender-Specific and Exercise-Dependent

Authors
A Lafoux, S Lotteau, C Huchet, S Ducreux

Lab
University of Lyon, INSERM, INRA, INSA Lyon, UniversitŽ Claude Bernard Lyon, Bron, France

Journal
Life

Abstract
The transient receptor potential vanilloid 1 (TRPV1) belongs to the transient receptor potential superfamily of sensory receptors. TRPV1 is a non-selective cation channel permeable to Ca2+ that is capable of detecting noxious heat temperature and acidosis. In skeletal muscles, TRPV1 operates as a reticular Ca2+-leak channel and several TRPV1 mutations have been associated with two muscle disorders: malignant hyperthermia (MH) and exertional heat stroke (EHS). Although TRPV1_/_ mice have been available since the 2000s, TRPV1Õs role in muscle physiology has not been thoroughly studied. Therefore, the focus of this work was to characterize the contractile phenotype of skeletal muscles of TRPV1-deficient mice at rest and after four weeks of exercise. As MS and EHS have a higher incidence in men than in women, we also investigated sex-related phenotype differences. Our results indicated that, without exercise, TRPV1_/_ mice improved in vivo muscle strength with an impairment of skeletal muscle in vitro twitch features, i.e., delayed contraction and relaxation. Additionally, exercise appeared detrimental to TRPV1_/_ slow-twitch muscles, especially in female animals.

BIOSEB Instruments Used:
Grip strength test (BIO-GS3)