TRP channels

TRP channels are a family of ion channels in cell membranes that open in response to temperature, chemical irritants, pressure or pH and let calcium and sodium enter the cell.

The name stands for transient receptor potential, and the family has more than two dozen members in humans grouped into subfamilies including TRPV (vanilloid), TRPA (ankyrin) and TRPM (melastatin). They are best known as the body's thermometers and chemical sensors: TRPV1 responds to heat and to capsaicin from chili peppers, TRPM8 to cold and menthol, and TRPA1 to pungent compounds like mustard oil and to inflammatory signals. Because so many sit on sensory nerve endings, TRP channels are central to how pain, itch and temperature are detected and to how inflammation makes tissue more sensitive.

Several cannabinoids interact with TRP channels in laboratory studies, which is why they are sometimes called ionotropic cannabinoid receptors. Cannabidiol activates and then desensitizes TRPV1 in cell models, and CBD, CBG and CBC act on TRPA1 and TRPM8 as well, offering proposed mechanisms for effects on pain and inflammation that do not involve CB1 or CB2. That work remains preclinical, and the relevance of these interactions at the concentrations reached in people is not established.