Solitary chemosensory cells explained

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 apparatuses). In the aquatic vertebrates, SCCs are also present in the skin. In oral cavity, SCCs precedes the development of taste buds. For long time, SCCs were considered to be typical of aquatic vertebrates. Recently, these elements were also demonstrated in mammals.

The SCCs share common morphological and biochemical characteristics with the taste cells located in taste buds of the oro-pharyngeal cavity. In particular, they may express molecules of the chemoreceptorial cascade (such as trans-membrane taste receptors, the G-protein gustducin, PLCbeta2, IP3R3, TRPM5). Morphologically, the elements of SCCs are polymorphic. Some of them have an apical tuft of rigid microvilli (brush cells). Other elements have secretory exocrine granules and others may have endocrine differentiation. Often these elements are innervated. In the upper respiratory system the SCCs are contacted by the sensory endings of trigeminal nerve fibers (SubP and CGRP immunoreactive).The SCCs of the aquatic vertebrates play a role in food search and predator avoidance. The functional role of the SCCs located in internal organs of mammals is unknown also if several hypotheses have been advanced. In nasal cavity, SCCs operate as sentinels being involved in detection of irritants and are important in the protection of the airway.

See also

• Diffuse chemosensory system
• Chemosensory clusters

References

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• 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.
• Tizzano M, Merigo F, Sbarbati A. Evidence of solitary chemosensory cells in a large mammal: the diffuse chemosensory system in Bos Taurus airways. J Anat2006; 209 (3): 333 – 7.
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External links

• SCC Discovery in fishes