Date of Award

Fall 10-28-2019

Degree Type

Thesis

Degree Name

MSOB (Master of Science in Oral Biology)

Primary Advisor

Dr. Marco Tizzano

Abstract

Taste in the gustatory system allows to distinguish between safe and harmful food, and to gauge its nutritional value. Digestive enzymes in saliva begin to dissolve food into base chemicals that are detected by taste buds containing three different cell types involved in the perception of the five basic tastes. Von Ebner's glands, found adjacent to the moats surrounding the circumvallate (CV) and foliate papillae, are exocrine salivary glands that secrete digestive enzymes and presumably flush material out of the papillae. Recently, we rediscovered and characterized anatomically and molecularly a chemosensory structure in the mouse oral cavity consisting of unorganized taste buds associated with ducts and a gland at the rear of the mandible, distal to the last molar and anterior to the ascending ramus. These taste buds appear to be the same ones first described by Iida in 1983, Miller in 1984, and characterized for sensory responses by Travers et al. in 1995 (Miller and Smith 1984, Travers and Norgren 1995). Here we used immunohistochemistry and RT-PCR to characterize this gingival chemosensory structure, consisting of taste buds and a minor salivary gland. Similar to the CV and foliate papillae, this novel retromolar chemosensory structure contains taste buds surrounding the orifice of ducts originating from a salivary gland (morphologically similar to the Von Ebner's glands). This salivary gland is located below the mucosa of the retromolar gap, extending posteriorly in the retromolar trigone. Above the gland and ducts, taste buds are positioned on the surface of the retromolar gingival epithelium, surrounding the duct orifices. We determined that these taste buds have chemosensory features expressing many canonical taste signaling elements, including taste receptors. The composition of the secretions from the retromolar gland is unknown. The retromolar taste buds are responsible for a small portion of sensory gustatory perception (Travers and Norgren 1995). Interestingly, patients have reported taste changes following procedures involving third molar extraction, possibly due to the disruption of the retromolar tissue (Shafer, Frank et al. 1999, Akal, Kucukyavuz et al. 2004, Klasser, Utsman et al. 2008, Ridaura-Ruiz, Figueiredo et al. 2012). The retromolar taste structure possibly plays a role in taste perception and represents a potential novel pharmacological target for taste or dry mouth disorders.

Available for download on Tuesday, October 27, 2020

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