Functions and species differences of softpalate taste buds in mammals

在软腭（SP）的味蕾中，味蛋白在几乎所有（96.7%）的IP 3R 3表达细胞中表达，而在菌状（FF）和轮状（CV）乳头中，味蛋白阳性细胞分别为IP 3R 3表达细胞的42.4%和60.1%。为了证实味蛋白在SP上的味觉转导中的广泛作用，记录了来自味蛋白-KO小鼠中三个主要味觉神经的电生理反应，并比较了神经之间的反应特性。与大鼠中的免疫组织化学结果一致，在gustducin-KO小鼠的岩浅大神经（GSP）中，对甜味和苦味刺激的神经反应显著降低。与GSP相反，鼓索神经（CT）和舌脊神经（GL）对甜味和苦味刺激的反应分别降低。免疫组化结果显示，SP中91.1%的IP 3R 3表达细胞为gustducin阳性。这些结果D ...更多信息 为了研究味蕾基底细胞的胚胎发育过程，采用原位杂交和免疫组织化学方法检测了味蕾基底细胞标志物Shh、Proxi和Mashi在小鼠胚胎中的表达。Proxi与Shh从Shh表达开始就在舌前区（E1 2.5）和软腭区（E14.5）以点状模式共表达，这表明味蕾的基底细胞和胚胎中的Shh表达点具有共同的特征。在这两个区域中，Mashi表达落后于Shh和Proxi表达约2天。神经到达上皮细胞表达Shh稍前发病的Mashi表达。这些结果表明，在味蕾的基底细胞的分化开始神经independent.We分析再生味蕾诱导的CT和GSP在大鼠和小鼠的交叉再生免疫组织化学和原位杂交。结果表明，不同神经供应的再生后，SP和FF中Gustducin和IP 3R 3的共表达不依赖于神经，而依赖于上皮。这一结果表明，交叉再生后仍然存在相同的功能差异。少

Gustducin was expressed in almost all (96.7%) IP3R3-expressing cells in taste buds of the soft palate (SP),whereas gustducin-positive cells were 42.4% and 60.1 % of IP3R3-expressing cells in the fungiform (FF) and circumvalate (CV) papillae, respectively. To confirm the broad role of gustducin in the taste transduction on the SP, responses from three major gustatory nerves in gustducin-KO mice were recorded electrophysiologically and the response properties were compared among the nerves. In consistent with the immunohistochemical results in the rat, nerve responses to both sweet and bitter stimuli were markedly reduced in the greater superficial petrosal nerve (GSP) of gustducin-KO mice. In contrast to the GSP, the chorda tympani nerve (CT) and the glossopharngeal nerve (GL) showed reduced responses to sweet and bitter stimuli, respectively. Immunohistochemistry of gustducin and IP3R3 in mice showed that 91.1% of IP3R3-expressing cells in the SP was gustducin positive. These results d … More emonstrate that gustducin is involved in the different lines of the taste-signaling pathway depending on the taste cell differentiation.To examine the embryonic development of the basal cells, the expression of the basal cell markers of taste buds (Shh, Proxi and Mashi) was determined in the mouse embryo by in situ hybridization and immunohistochemistry. Proxi was co-expressed with Shh from the beginning of Shh expression in a punctate pattern on the anterior tongue (E1 2.5) and soft palatal region (E14.5),suggesting that the basal cells of taste buds and Shh-expressing spots in embryos share common features. Mashi expression lagged behind the expression of Shh and Proxi by approximately 2 days in both regions. Nerves reached the epithelium expressing Shh slightly before the onset of Mashi expression. These results suggest that the differentiation of the basal cells in the taste bud starts nerve-independently.We analyzed regenerated taste buds induced by cross-regeneration of CT and GSP in rats and mice using immunohistochemistry and in situ hybridization. The results showed that the gustducin and IP3R3 co-expression between in the SP and FF after the regeneration with the different nerve supply were not depend on the nerve but on the epithelium. This result suggests that the same functional difference still remain after the cross-regeneration. Less