TRP channels are a large family (about 28 genes) of plasma membrane, non-selective cationic channels that are either specifically or ubiquitously expressed in excitable and non-excitable cells.¹ The TRP channels have six putative transmembrane domains (TM) with a pore domain between the fifth and the sixth TM, and all assemble as tetramers. Both the N- and the C-terminus of all TRPs are intracellular.³

According to IUPHAR, the TRP family is composed of three main subfamilies on the basis of sequence homology; TRPC, TRPM and TRPV (to date, three additional subfamilies are also considered to belong to the TRP family: the TRPA, TRPML, and TRPP).^1-4 The TRPV subfamily consists of six members, TRPV1-6.⁵

Four members of the TRPV family have been described as a thermosensitive ion channels (TRPV1 to TRPV4). Each channel exhibits distinct thermal activation thresholds ranging from noxious cold (<17°C) to noxious heat (>52°C).^6,7

TRPV3 is highly expressed in skin keratinocytes. It forms a nonselective cation channel that is activated by hot temperatures in the innocuous and noxious range. The channel is also expressed in oral and nasal cavities where it has been postulated to play a role in flavor sensation. TRPV3 is also implicated as a molecular target of some allergens and skin sensitizers.⁸