Chemesthesis is the detection of potentially harmful chemicals by the skin and mucous membranes. Chemesthetic sensations arise when

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

s activate

receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and respond ...

s associated with other

sense A sense is a biological system used by an organism for sensation, the process of gathering information about the surroundings through the detection of Stimulus (physiology), stimuli. Although, in some cultures, five human senses were traditio ...

s that mediate

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

touch The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of bo ...

, and thermal perception. These chemical-induced reactions do not fit into the traditional sense categories of

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste. Taste is the perception stimulated when a substance in the mouth biochemistry, reacts chemically with taste receptor cells l ...

and smell. Examples of chemesthetic sensations include the burn-like irritation from

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) (, rarely ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a potent Irritation, irritant for Mammal, mammals, including humans, and produces ...

and related compounds in foods like

chili pepper Chili peppers, also spelled chile or chilli ( ), are varieties of fruit#Berries, berry-fruit plants from the genus ''Capsicum'', which are members of the nightshade family Solanaceae, cultivated for their pungency. They are used as a spice to ...

s; the coolness of

menthol Menthol is an organic compound, specifically a Monoterpene, monoterpenoid, that occurs naturally in the oils of several plants in the Mentha, mint family, such as Mentha arvensis, corn mint and peppermint. It is a white or clear waxy crystallin ...

in mouthwashes and topical analgesic creams; the stinging or tingling of carbonated beverages in the nose and mouth; the tear-induction of cut onions; and the pungent, cough-inducing sensation in the back of the throat elicited by the

oleocanthal Oleocanthal is a phenylethanoid, or a type of natural phenolic compound found in extra-virgin olive oil. It appears to be responsible for the burning sensation that occurs in the back of the throat when consuming such oil. Oleocanthal is a tyro ...

in high-quality extra virgin olive oil. Some of these sensations may be referred to as spiciness,

pungency Pungency ( ) is the taste of food commonly referred to as spiciness, hotness or heat, found in foods such as chili peppers. Highly pungent tastes may be experienced as unpleasant. The term piquancy ( ) is sometimes applied to foods with a lower ...

, or piquancy. Chemesthetic sensations sometimes arise by direct chemical activation of ion channels on sensory nerve fibers, for example of

transient receptor potential channel Transient receptor potential channels (TRP channels) are a group of ion channels located mostly on the plasma membrane of numerous animal cell types. Most of these are grouped into two broad groups: Group 1 includes TRPC ( "C" for canonical), TRP ...

s including those of the

TRPV TRPV is a family of transient receptor potential cation channels (TRP channels) in animals. All TRPVs are highly calcium selective. TRP channels are a large group of ion channels consisting of six protein families, located mostly on the plasm ...

, TRPA or TRPM 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 called solitary chemosensory cells which release

acetylcholine Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...

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 of cornified skin. Much of the chemesthetic flavor sensations are mediated by the trigeminal 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 trigeminal

stimulant Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognition, ...

References

Further reading