Transient receptor potential ankyrin 1 (TRPA1)

Transient receptor potential ankyrin 1, or TRPA1, is an ion channel on sensory nerve endings that detects irritating chemicals, cold and tissue damage and signals pain.

TRPA1 is expressed mainly on the same pain-sensing neurons that carry TRPV1, and it opens in response to the pungent compounds in mustard, wasabi, garlic and cinnamon, to cigarette smoke, tear gas and formaldehyde, and to by-products of oxidative stress generated inside the body during inflammation. When it opens, calcium and sodium enter the nerve ending, which fires and also releases peptides that widen blood vessels and cause local swelling, a process called neurogenic inflammation. It is sometimes called the wasabi receptor.

Because it responds to so many irritants, TRPA1 is a target in research on cough, itch, migraine and inflammatory pain, though no TRPA1 drug has reached approval. Cannabinoids including CBD activate and then desensitize TRPA1 in cell experiments, one of several non-cannabinoid-receptor interactions attributed to CBD; the relevance of this to sensation in people has not been established.