Chemesthesis is the detection of potentially harmful chemicals by the skin and mucous membranes.[1] Chemesthetic sensations arise whenchemical compounds activatereceptors associated with othersenses that mediatepain,touch, andthermal perception. These chemical-induced reactions do not fit into the traditional sense categories oftaste andsmell.
Examples of chemesthetic sensations include the burn-like irritation fromcapsaicin and related compounds in foods likechili peppers; the coolness ofmenthol in mouthwashes and topical analgesic creams; the stinging or tingling ofcarbonated beverages in the nose and mouth;[2] the tear-induction of cut onions;[3] and the pungent, cough-inducing sensation in the back of the throat elicited by theoleocanthal in high-qualityextra virgin olive oil.[4] Some of these sensations may be referred to as spiciness,pungency, or piquancy.[5]
Chemesthetic sensations sometimes arise by direct chemical activation of ion channels on sensory nerve fibers, for example oftransient receptor potential channels including those of theTRPV,TRPA orTRPM subtypes. Alternatively, irritant chemicals may activate cells of the epithelium to release substances that indirectly activate the nerve fibers. The respiratory passages, including the nose and trachea, possess specialized cells calledsolitary chemosensory cells[6] which releaseacetylcholine[7] or other activators to excite nearby nerve fibers.
Because chemoresponsive nerve fibers are present in all types of skin, chemesthetic sensations can be stimulated from anywhere on the body's surface as well as from mucosal surfaces in the nose, mouth, eyes, etc. Mucous membranes are generally more sensitive to chemesthetic stimuli because they lack the barrier function ofcornified skin.
Much of the chemesthetic flavor sensations are mediated by thetrigeminal nerves, large nerves responsible for motor functions and sensation in the face. Flavors that stimulate the trigeminal nerves are therefore important. For example, the carbon dioxide in carbonated beverages is a trigeminalstimulant.[3]
Chemesthesis is the detection of chemical irritants or toxins by cutaneous neurons and is an important underlying chemosensory process.
Long referred to as the 'common chemical sense' and frequently described imprecisely as 'trigeminal sensitivity', chemesthesis provides the burn of chili pepper, the coolness of menthol and the tingle of carbonation.
