The expression of receptors for endocannabinoids in human and rodent skeletal muscle

The endocannabinoid system is a lipid derived signalling system that has been shown to regulate appetite and energy metabolism. The most abundant endogenous endocannabinoid, anandamide, has been shown to activate the cannabinoid receptor type 1 (CB1) and type 2 (CB2) as well as the 'non-cannabinoid' transient receptor potential channel-vanilloid sub-family member 1 (TRPV1), before being rapidly metabolised by fatty acid amide hydrolase (FAAH). We have previously demonstrated the expression of CB1 and studied the effects of CB1 activation and inhibition in human skeletal muscle myotubes, however, not all results could be explained by CB1 mediated effects. This suggests that other receptors which are activated by endocannabinoids may be present in skeletal muscle. In this study we describe the presence of not only CB1, but also CB2, TRPV1 and the degrading enzyme FAAH in human and rodent skeletal muscle using reverse transcription polymerase chain reaction (RT-PCR).