The diffuse chemosensory system (DCS) is an anatomical structure composed of

solitary chemosensory cells {{More footnotes needed, date=October 2018 Solitary chemosensory cells (SCCs) (also called solitary chemoreceptor cells) are isolated elements located in epithelia of the apparatuses of endodermic origin (such as respiratory and digestive apparatuse ...

and chemosensory clusters. The concept of DCS has been advanced in 2005, after the discovery that cells similar to

gustatory The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

elements are present in several organs of the

respiratory The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies grea ...

and digestive apparatuses. The elements forming the DCS share common morphological and

biochemical Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology an ...

characteristics with the taste cells located in

taste buds Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the che ...

of the oropharyngeal cavity. In particular, they may express

molecules A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

of the chemoreceptorial cascade (e.g. trans-membrane

taste The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

receptors, the

G-protein G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their act ...

gustducin Gustducin is a G protein associated with taste and the gustatory system, found in some taste receptor cells. Research on the discovery and isolation of gustducin is recent. It is known to play a large role in the transduction of bitter, sweet a ...

, PLCbeta2, IP3R3, TRPM5). Morphologically, the elements of the DCS are polymorphic. Some of them have an apical tuft of rigid

microvilli Microvilli (singular: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, ...

(brush cells). Other elements have secretory

exocrine Exocrine glands are glands that secrete substances on to an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucous. Exocrine glands are one of t ...

granules and others may have endocrine differentiation. Often these elements are innervated. To date, the functional role for the DCS is unknown also if several

hypotheses A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obser ...

have been advanced. Questions remain about the role of the diffuse

chemosensory A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance ( endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecep ...

system in control of complex functions (e.g.

airway The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose to th ...

surface liquid secretion) and about the involvement of chemoreceptors in

respiratory disease Respiratory diseases, or lung diseases, are pathology, pathological conditions affecting the organs and tissues that make gas exchange difficult in Breathing, air-breathing animals. They include conditions of the respiratory tract including the t ...

s. The chemoreceptive capacity of the DCS seems to protect against

exogenous In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It contrasts with endogeneity or endogeny, the fact of being influenced within a system. Economics In an economic model, an exogeno ...

substances.

References

{{reflist *Sbarbati A, Osculati F. The taste cell-related diffuse chemosensory system. Prog Neurobiol 2005; 75: 295–307. *Gilbertson TA, Damak S, Margolskee RF. The molecular physiology of taste transduction. Curr Opin Neurobiol 2000; 10: 519–27. *Höfer D, Drenckhahn D. Cytoskeletal markers allowing discrimination between brush and other epithelial cells of the gut including etnteroendocrine cells. Histochem Cell Biol 1996; 105:405 –12. *Höfer D, Drenckhahn D. Identification of the taste cell G-protein alpha-gustducin in brush cells of the rat pancreatic duct system. Histochem Cell Bio1998; 110: 303–309. *Höfer D, Puschel B, Drenckhahn D. Taste receptor-like cells in the rat gut identified by expression of α-gustducin. Proc Natl Acad Sci USA 1996; 93: 6631– 34. *Merigo F, Benati D, Tizzano M, Osculati F, Sbarbati A. α-gustducin immunoreactivity in the airways. Cell Tissue Res 2005; 319: 211–19. *Merigo F, Benati D, DiChio M, Osculati F, Sbarbati A. Secretory cells of the airway express molecules of the chemoreceptive cascade. Cell Tissue Res 2007; 327: 231-247. *Sbarbati A, Crescimanno C, Benati D, Osculati F. Solitary chemosensory cells in the developing chemoreceptorial epithelium of the vallate papilla. Journal of Neurocytology 1998; 27:631–35. *Sbarbati A, Crescimanno C, Bernardi P, Osculati F. Alpha-gustducin immunoreactive solitary chemosensory cells in the developing chemoreceptorial epithelium of the rat vallate papilla. Chem senses 1999; 24:469–72. *Sbarbati A., Merigo F, Benati D, Tizzano M, Bernardi P, Crescimanno C, Osculati F. Identification and characterization of a specific sensory epithelium in the rat larynx. J Comp Neurol 2004a; 475:188-201. *Sbarbati A., Merigo F, Benati D, Tizzano M, Bernardi P, Osculati F. Laryngeal chemosensory clusters. Chem Senses 2004b; 29:683-92. Sensory systems Sensory receptors