Glycoconjugates and keratin 18 define subsets of taste cells

Abstract

Sections of neonatal, normal adult and denervated adult rat tongue were examined with lectin histochemistry. Attention was focused upon intragemmal cells (cells within the taste bud) and the surrounding perigemmal cells. Informative staining patterns were observed with four of 12 lectins: Ulex europaeus (UEA-I), Bauhinia purpurea (BPA), Helix pomatia (HPA) and Lotus tetragonolobus (LTA) agglutinins. In normal adult tongues, BPA bound to those lingual epithelial cells lacking contact with the basal lamina. After they formed, vallate taste buds were laterally surrounded by distinctive BPA-positive cells. HPA reacted selectively with 28% and LTA with 23% of the intragemmal cells in vallate/foliate taste buds. In double-stained taste buds there was a statistically significant overlap of LTA-positive cells and keratin 18-positive cells. The overlap between HPA binding and keratin 18 was more marked: double-stained cells comprized 67% of all stained cells. During taste bud development in neonates keratin 18 synthesis preceded HPA binding. In contrast, during the replacement of adult taste cells, keratin 18 synthesis and HPA binding were generally concurrent. Keratin 18 and HPA probably identify the same subset of older taste receptor cells. HPA may bind to glycoconjugates on the surface of keratin 18-positive cells. In denervated adult tongue the loss of all UEA-I-positive or BPA-positive perigemmal cells suggests that perigemmal as well as intragemmal cells are nerve-dependent.

Brush Cells of the Mouse Intestine Possess a Specialized Glycocalyx as Revealed by Quantitative Lectin Histochemistry: Further Evidence for a Sensory Function

“…Takami et al (1994) reported that the receptor cells of the olfactory epithelium and the vomeronasal organ differ from other epithelial cells of the nasal cavity in their glycoconjugate composition. Similar peculiarities have been reported for the receptor cells in the vestibular end organs (Takumida and Bagger-Sjöbäck 1991) and for those in the taste buds (Witt and Miller 1992;Zeng et al 1995). Interestingly, the taste bud receptors of rats contain high amounts of cytokeratin 18 (Zeng et al 1995) and thus further resemble the brush cells .…”

“…Similar peculiarities have been reported for the receptor cells in the vestibular end organs (Takumida and Bagger-Sjöbäck 1991) and for those in the taste buds (Witt and Miller 1992;Zeng et al 1995). Interestingly, the taste bud receptors of rats contain high amounts of cytokeratin 18 (Zeng et al 1995) and thus further resemble the brush cells . Although it has been demonstrated that brush cells of the trachea may directly contact afferent nerves (Luciano et al 1968), this is normally not the case for brush cells at other locations.…”

Comparative Lectin Histochemical Studies on Taste Buds in Five Orders of Mammals

“…Since beta-N-acetylglucosamine is ubiquitously localized in all types of papillae in all mammals examined, it might play an essential role in the taste bud function. As for alpha-fucose, the present results positively correlated with the previous reports on the localizations of glycoconjugates in the rat [4], rabbit, frog and fish [3,4,[14][15][16][17][18]. In contrast, certain glycoconjugates were unique in some but not all types of papillae, such as alpha-N-acetylgalactosamine, alpha-mannose and alpha-D-glucose.…”

“…Based on the molecular structures of these receptors, it has been postulated that at least some of the receptors are glycoproteins, exposed to the extra-cellular surface of taste cells [7], and supposed to have a role in perceiving taste sensations. On the other hand, although several lectin histochemical studies have been reported until now, all of them reported only on a single species, such as rabbits [15], frogs [3] and teleost [16][17][18] and rats [4,14]; and no comparative studies have been made on different mammalian species in one report. In the present study, therefore, we lectin histochemically examined the cells of taste buds in the lingual papillae to determine and compare the types and compositions of glycoconjugates in five orders of mammalian species: artiodactyl, perissodactyl, rodent, carnivore and primate.…”

Analysis of the distribution of binding sites for the plant lectin Bandeiraea simplicifolia I‐isolectin B4 on primary sensory neurones in seven mammalian species

“…Consistent with this idea is the expression of different glycoconjugates by distinct functional classes of cells in the visual (Chan et al, 1999), respiratory (Kasper and Singh, 1995;BurkhardtHolm, 1997;Dorscheid et al, 1999), gustatory (Zeng et al, 1995), olfactory (Taniguchi et al, 1993;Shnayder-Shapiro et al, 1995;Nakajima et al, 1998;, gastrointestinal (Sato and Spicer, 1982;Falk et al, 1994;Ge et al, 1998;Gebhard and Gebert, 1999;Poorkhalkali et al, 1999), reproductive (Zhou et al, 1994;Arenas et al, 1998;Romo et al, 1999), and immune (Clark et al, 1995;Sharma et al, 1996;Foster et al, 1998) systems in a variety of mammalian species.…”