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Quantitative differences between taste buds in mouse fungiform papillae and soft palates
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ohtubo, Yoshitaka Yoshii, Kiyonori |
| Copyright Year | 2007 |
| Abstract | s / Neuroscience Research 58S (2007) S1–S244 S217 P3-f20 Glutamate responses of mouse fungiform taste cells with action potentials Yoshihiro Murata, Ryusuke Yoshida, Toshiaki Yasuo, Keiko Yasumatsu, Noriatsu Shigemura, Yuzo Ninomiya Sec. Oral Neurosci., Grad. Sch. Dental Sci., Kyushu University, Fukuoka, Japan Glutamate is one of the transmitter candidates for cell communication in taste buds as well as a umami compound. To investigate the dual functions of glutamate in taste cell activity, we recorded action potentials from single taste cells when glutamate is apically or basolaterally applied to the taste buds isolated from mouse fungiform papillae. The apical application of 100–300 mM monosodium glutamate (MSG) induced an increase in firing frequency in a subset of the taste cells. The response profile of these cells was classified into four categories by best stimulus and synergistic response with inosine monophosphate. The basolateral application (<1 mM) changed the spontaneous spike frequency in some of the taste cells responding to apical MSG, suggesting that basolateral glutamate modulates the basal activity of MSG-sensitive taste cells. Our results support the hypothesis that glutamate functions both as an umami compound and as a modulator of taste cell activity. Research funds: JSPS Grants-in-Aid 18077004, 18109013 (YN) and 17791325 (RY) P3-f21 Taste receptor cells generating action potentials within a single taste bud of mouse fungiform papillae Ryusuke Yoshida, Yoshihiro Murata, Toshiaki Yasuo, Keiko Yasumatsu, Noriatsu Shigemura, Yuzo Ninomiya Sect. of Oral Neurosci., Grad. Sch. of Dental Sci., Kyushu University, Fukuoka, Japan We have recently shown that taste receptor cells generating action potentials are the cells that transmit major taste information to gustatory nerve fibers. However, it is unclear whether these cells in a single taste bud would possess different taste selectivity or they would share the same taste selectivity. Here, we recorded action potentials from more than two different taste cells within a single taste bud separately or simultaneously by using a loose patch recording technique, and compared their taste selectivity to four conventional taste stimuli. In some cases, two taste cells in a bud responded to the same class of taste stimuli, whereas in other cases they did to different classes of taste stimuli, such as saccharin versus quinine, saccharin versus NaCl, etc. These results suggest that a single taste bud may contain the plural numbers of taste receptor cells having similar and different taste responsiveness. Research funds: KAKENHI 18077004, 18109013 (YN) and 17791325 (RY) P3-f22 Voltage-gated currents of taste bud cells in infant mice Masafumi Iwamoto, Yoshitaka Ohtubo, Kiyonori Yoshii Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan In adult mouse taste bud cells, the magnitude of voltage-gated currents depended on their cell types. The magnitude of Na+ and outward currents was much smaller in type I cells than in other cell types, and that of TEA-insensitive outward currents was much larger in type II cells than in the others. Here we show that these relations are inapplicable to infant counterparts; some infant type II cells fail to elicit either Na+ or outward currents though adult type II cells elicited both currents, and their currents elicited are much smaller in magnitude than that of adult type II cells. We also show that the number of taste bud cells increases markedly during the infant period. These results suggest that newborn type II cells express molecules involved in a taste transduction cascade such as G-protein -13, PLC 2, and IP3R3, before increasing the number of functional voltage-gated channels. Research funds: 21st century COE program in K.I.T. and a Grants-in-Aid for Scientific Research (#16300094) from JSPS P3-f23 Polymorphisms of ENaC subunits relate to mouse strain differences in amiloride sensitive salt responses Noriatsu Shigemura1, Tadahiro Ohkuri1, Chiharu Sadamitsu1, Keiko Yasumatsu1, Ryusuke Yoshida1, Gary K. Beauchamp2, Alexander A. Bachmanov2, Yuzo Ninomiya1 1 Oral Neurosci. Dent. Sci., Kyushu Univ., Japan; 2 Monell Chemical Senses Center, USA Amiloride, epithelial Na+ channel bloker, is known to inhibit NaCl responses of the chorda tympani (CT) nerve innervating anterior tongue in mice. C57BL/6(B6) exhibited inhibition of NaCl responses by amiloride to −50% of control, whereas slightly inhibition (−20%) was observed in 129P3/J(129) mice. Amiloride-sensitive epithelial Na+ channel (ENaC) is a potent candidate for salt taste receptor. In this study, using B6, 129 and their F2 hybrids, we investigated possible relationships between the amiloride sensitivity and SNPs of ENaC subunits ( , , ). Sequencing analysis detected a SNP resulted in an amino acid substitution, R616W, in subunit. Responses of the CT nerve to NaCl decreased after amiloride treatment in B6 and F2( R616W genotypes: B6/129 and B6/B6), whereas only weak inhibition was evident in 129 and F2(129/129). These results suggest that R616W may be one of factors responsible for mouse strain differences in amiloride sensitive salt responses. P3-f24 Modulations of sweet taste responses by salts, acids and bitter compounds in the mouse chorda tympani nerve Keiko Yasumatsu1, Ryusuke Yoshida1, Robert F. Margolskee2, Yuzo Ninomiya1 1 Sect. Oral Neurosci., Grad. Sch. Dent. Sci., Kyushu University, Fukuoka, Japan; 2 Department of Neuroscience, the Mount Sinai School of Medicine, United States To investigate gustatory mixture interactions, responses to sweet compounds with and without salts, acids and bitter compounds were examined in the chorda tympani nerve of wild type (WT) and TRPM5-KO mice. In WT mice, whole nerve responses to 0.1–0.5 M sucrose increased when they were mixed with 30 mM NaCl (more than the sum of response to each component), whereas no such increase of sucrose responses was observed when mixed with 1–10 mM HCl. Responses to 0.3 M sucrose were suppressed to ∼60% of control by addition of 3–10 mM QHCl. Consistently, responses of sweet-sensitive fibers to sucrose were significantly suppressed by 1–10 mM QHCl. In contrast, sucrose responses in TRPM5KO mice were not affected by QHCl. These results suggest that sweet taste responses are modulated by other taste substances at peripheral taste cell level and that TRPM5 may be involved in the pathway responsible for inhibition of sucrose responses by QHCl. P3-f25 Quantitative differences between taste buds in mouse fungiform papillae and soft palates Yoshitaka Ohtubo, Kiyonori Yoshii Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Japan The different taste responsiveness of the chorda tympani nerve and the greater petrosal nerve suggested the dissimilar expression of taste transduction proteins such as SNAP-25, IP3R3, G 13 and G gustducin in the taste bud cells innervated by them. We investigated their expression immunohistochemically; the density (cells/ m2) of immunoreactive cells (IRCs) per single taste buds in both regions was calculated by slicing each taste bud optically and horizontally with a confocal microscope. The density of G 13and G gustducin-IRCs was higher in soft palate taste bud innervated by the greater petrosal nerve than that in fungiform taste bud innervated by the chorda tympani nerve. The density of SNAP-25and IP3R3-IRCs did not differ. The present results suggest that the dissimilar expression of G proteins contributes to the differences in the neural responsiveness. Research funds: 21th century COE program in K.I.T. and a Grants-in-Aid for Scientific Research (#16300094) from JSPS |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/j.neures.2007.06.1006 |
| Volume Number | 58 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/S0168010207014915 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/S0168010207014915?dgcid=api_sd_search-api-endpoint |
| Alternate Webpage(s) | https://doi.org/10.1016/j.neures.2007.06.1006 |
| Journal | Neuroscience Research |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
