Identification of the taste cell G-protein, α-gustducin, in brush cells of the rat pancreatic duct system

Abstract

The major pancreatic excretory ducts have been shown to contain a large number of specialized epithelial cells, named brush cells, that are characterized by an apical tuft of stiff microvilli. The function of pancreatic brush cells is unknown. Because of some structural similarities to taste receptor cells of the tongue, we addressed the question whether pancreatic brush cells contain the taste cell-specific GTP-binding protein, alpha-gustducin, and hence might be considered to be involved in intraductal chemoreception. By immunostaining, we show that ductal brush cells of the rat pancreatic duct system contain alpha-gustducin, which is concentrated in the apical tuft of microvilli and is also found along the basolateral cell surface. A further outcome of this study is that brush cells are concentrated in the terminal portions of extralobular ducts and in the major pancreatic duct where brush cells comprise up to 22% of the ductal epithelium. Immunoblotting of the major pancreatic duct revealed a 42-kDa band that comigrated with alpha-gustducin of the rat tongue. In view of our previous observation that the ductal brush cells are particularly rich in nitric oxide synthase-I, there is reason to assume that these cells might play a role in certain aspects of chemoreceptive signalling. Thus, chemosensory control of pancreatic secretion might occur at two independent sites, the intestine and the terminal portions of the excretory duct system.

Amino acid taste receptor regulates insulin secretion in pancreatic β-cell line MIN6 cells

“…Furthermore, these taste-sensing mechanisms are involved in more general endocrine and neuroendocrine functions via their expression in pancreas (Hofer & Drenckhahn 1998;Nakagawa et al 2009) and hypothalamic neurons (Ren et al 2009). The expression of taste sensors in pancreatic b-cells, on the other hand, is less likely to have been anticipated to date.…”

Dynamic Expansion of Gastric Mucosal Doublecortin-Like Kinase 1–Expressing Cells in Response to Parietal Cell Loss Is Regulated by Gastrin

“…1 Although tuft cells in many organs are considered a type of solitary chemosensory cell that expresses taste receptors for chemical transduction, 5 the function of gastric tuft cells remains unknown.…”

“…4 Tuft cells represent a class of solitary chemosensory cells, because they express several chemoreceptor molecules, such as the guanine nucleotide binding protein a-transducing 3 and the G-proteinecoupled taste receptor type 1 member 3. 5 Although tuft cells are continuously renewed in the epithelial cell layer, mitotic tuft cells have not been observed. These findings suggest that tuft cells are post-mitotic and might originate from other sources.…”

Espin cytoskeletal proteins in the sensory cells of rodent taste buds

“…Type II cells also bear a resemblance to brush cells and solitary chemoreceptor cells in the digestive and respiratory tracts Sbarbati & Osculati, 2005). Like a subset of type II taste cells, brush cells and solitary chemoreceptor cells express α-gustducin (Höfer & Drenckhahn, 1998;Sbarbati et al, 2004;Sekerková et al, 2004) and possess short apical microvilli with core actin bundle rootlets that reach deep into the cell . We showed previously that solitary chemoreceptor cells in the vomeronasal organ contain espin and α-gustducin (Sekerková et al, 2004), and we have also detected espin + brush cells in a variety of other locations (our unpublished results).…”