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. According to IUPHAR the TRP family comprises of three main subfamilies on the basis of sequence homology; TRPC, TRPM and TRPV (to date, three extra subfamilies are considered to belong to the TRP family; the TRPA, TRPML, and TRPP). The TRPV subfamily consists of six members, TRPV1-6.
TRPV4 (also named OTRPC4) is activated under hypotonic conditions and serves as an osmoreceptor. TRPV4 is expressed in brain, liver, kidney, heart, testis and salivary gland.