Transient receptor potential channels (TRP channels) are a group of
ion channels located mostly on the
plasma membrane of numerous animal cell types. There are about 28 TRP channels that share some structural similarity to each other. These are grouped into two broad groups: Group 1 includes
TRPC ( "C" for canonical),
TRPV ("V" for vanilloid),
TRPM ("M" for melastatin),
TRPN, and
TRPA. In group 2, there are
TRPP ("P" for polycystic) and
TRPML ("ML" for mucolipin). Many of these channels mediate a variety of sensations like the sensations of pain, hotness, warmth or coldness, different kinds of tastes, pressure, and vision. In the body, some TRP channels are thought to behave like microscopic thermometers and used in animals to sense hot or cold. Some TRP channels are activated by molecules found in spices like garlic (
allicin), chilli pepper (
capsaicin), wasabi (
allyl isothiocyanate); others are activated by
menthol,
camphor, peppermint, and cooling agents; yet others are activated by molecules found in
cannabis (i.e.,
THC,
CBD and
CBN). Some act as sensors of osmotic pressure, volume, stretch, and vibration. These
ion channels are relatively non-selectively permeable to
cations, including
sodium,
calcium and
magnesium. TRP channels were initially discovered in
trp-mutant strain of the fruit fly
Drosophila. Later, TRP channels were found in vertebrates where they are ubiquitously expressed in many cell types and tissues. Most TRP channels are composed of 6
membrane-spanning
helices with intracellular N- and
C-termini. Mammalian TRP channels are activated and regulated by a wide variety of stimuli and are expressed throughout the body.