Chemesthesis
Encyclopedia
Chemesthesis is defined as the chemical sensibility of the skin and mucus membranes. Chemesthetic sensations arise when chemical compound
s activate receptor
s associated with other sense
s that mediate pain
, touch, and thermal perception. These chemical-induced reactions do not fit into the traditional sense categories of taste
and smell
. Examples of chemesthetic sensations include the burn-like irritation from chili pepper
, the coolness of menthol
in mouthwashes and topical analgesic creams, the stinging or tingling of carbonation in the nose and mouth, and the tear-induction of onions. These sensations also can be referred to as spicy qualities or piquance
.
Chemesthetic sensations arise by direct chemical activation of ion channels on sensory nerve fibers, e.g. of Transient receptor potential channel including those in the TRPV
, TRPA
or TRPM
subtypes. Alternatively, irritant chemicals may activate cells of the epithelium to release substances that may active the nerve fibers indirectly. The respiratory passages including nose and trachea, possess specialized cells, called solitary chemosensory cells
which release acetylcholine
or other activators to excite nearby nerve fibers.
Because chemoresponsive nerve fibers are present in all types of skin, chemesthetic sensations can be aroused from anywhere on the body's surface as well as from mucosal surfaces in the nose, mouth, eyes, etc. Mucus 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, which are relatively large and important nerves. Flavors that stimulate the trigeminal nerves are therefore important - for example, carbon dioxide is the trigeminal stimulant in carbonated beverages.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s activate receptor
Sensory receptor
In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...
s associated with other sense
Sense
Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...
s that mediate pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
, touch, and thermal perception. These chemical-induced reactions do not fit into the traditional sense categories of taste
Taste
Taste is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc....
and smell
Smell
Smell may refer to:* Olfaction, sense of smell, the ability of humans and other animals to perceive odors* Odor, the percept resultant from the sense of smell...
. Examples of chemesthetic sensations include the burn-like irritation from chili pepper
Chili pepper
Chili pepper is the fruit of plants from the genus Capsicum, members of the nightshade family, Solanaceae. The term in British English and in Australia, New Zealand, India, Malaysia and other Asian countries is just chilli without pepper.Chili peppers originated in the Americas...
, the coolness of menthol
Menthol
Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. The main form of menthol occurring in nature is -menthol, which is assigned...
in mouthwashes and topical analgesic creams, the stinging or tingling of carbonation in the nose and mouth, and the tear-induction of onions. These sensations also can be referred to as spicy qualities or piquance
Piquance
Piquance is a sensation associated with the sense of taste. In various Asian countries it has traditionally been considered a basic taste.-Etymology:...
.
Chemesthetic sensations arise by direct chemical activation of ion channels on sensory nerve fibers, e.g. of Transient receptor potential channel including those in the TRPV
TRPV
TRPV is a family of transient receptor potential ion channels. These channels are selective for calcium and magnesium over sodium ions. Like other members of the TRP superfamily, TRPV channels can be activated through seemingly disparate mechanisms...
, TRPA
TRPA (channel)
TRPA is a family of transient receptor potential ion channels.The sole member of the TRPA sub-family, TRPA1, contains 14 N-terminal ankyrin repeats and is believed to function as a mechanical stress sensor. It is expressed in the dorsal root ganglion, trigeminal ganglion, and hair cells...
or TRPM
TRPM
TRPM is a family of transient receptor potential ion channels . Functional TRPM channels are believed to form tetramers....
subtypes. Alternatively, irritant chemicals may activate cells of the epithelium to release substances that may active the nerve fibers indirectly. The respiratory passages including nose and trachea, possess specialized cells, called solitary chemosensory cells
Solitary chemosensory cells
Solitary chemosensory cells are isolated elements located in epithelia of the apparatuses of endodermic origin . In the aquatic vertebrates, SCCs are also present in the skin. In oral cavity, SCCs precedes the development of taste buds...
which release acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...
or other activators to excite nearby nerve fibers.
Because chemoresponsive nerve fibers are present in all types of skin, chemesthetic sensations can be aroused from anywhere on the body's surface as well as from mucosal surfaces in the nose, mouth, eyes, etc. Mucus 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, which are relatively large and important nerves. Flavors that stimulate the trigeminal nerves are therefore important - for example, carbon dioxide is the trigeminal stimulant in carbonated beverages.