Transient receptor potential vanilloid 1 (TRPV1) as a new target for osteoarthritis-related pain: a commentary on “Sensitization of TRPV1 by protein kinase C in rats with mono-iodoacetate-induced joint pain

Transient receptor potential vanilloid 1 (TRPV1) is a 6-transmembrane ionotropic receptor expressed in peripheral sensory dorsal root ganglion neurons and the dorsal horn of the spinal cord. This receptor was first described in 1997 as responsive to capsaicin and is known to play important roles in noxious stimuli (capsaicin, heat, acid, and endogenous ligands) and allodynia in inflammatory pain. Sensitization of TRPV1 is provoked by phosphorylation of its two Ser residues (Ser502 and Ser800), which occurs secondary to phosphorylation of protein kinase C (PKC) by extracellular inflammatory mediators, including ATP and bradykinin, released from surrounding inflamed tissues. Especially, PKCε plays a key role through its predominant involvement in primary afferent nociceptors (1).