Salt taste is one of the 5 basic taste qualities. Depending on the concentration, table salt is perceived either as appetitive or aversive, suggesting the contribution of several mechanisms to salt taste, distinguishable by their sensitivity to the epithelial sodium channel (ENaC) blocker amiloride. A taste-specific knockout of the α-subunit of the ENaC revealed the relevance of this polypeptide for low-salt transduction, whereas the response to other taste qualities remained normal. The fully functional ENaC is composed of α-, β-, and γ-subunits. In taste tissue, however, the precise constitution of the channel and the cell population responsible for detecting table salt remain uncertain. In order to examine the cells and subunits building the ENaC, we generated mice carrying modified alleles allowing the synthesis of green and red fluorescent proteins in cells expressing the α- and β-subunit, respectively. Fluorescence signals were detected in all types of taste papillae and in taste buds of the soft palate and naso-incisor duct. However, the lingual expression patterns of the reporters differed depending on tongue topography. Additionally, immunohistochemistry for the γ-subunit of the ENaC revealed a lack of overlap between all potential subunits. The data suggest that amiloride-sensitive recognition of table salt is unlikely to depend on the classical ENaCs formed by α-, β-, and γ-subunits and ask for a careful investigation of the channel composition.

中文翻译：

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ENaC亚基在味觉细胞中的分离表达。

盐味是5种基本口味品质之一。视浓度而定，食盐被认为具有食欲或厌恶性，提示几种机制对食盐味的贡献，可通过其对上皮钠通道（ENaC）阻断剂阿米洛利的敏感性加以区分。ENaC的α-亚基的味觉特异性敲除揭示了该多肽与低盐转导的相关性，而对其他味觉质量的响应仍然正常。完整功能的ENaC由α-，β-和γ亚基组成。然而，在味觉组织中，通道的精确组成和负责检测食盐的细胞群仍然不确定。为了检查构建ENaC的细胞和亚基，我们产生了携带修饰等位基因的小鼠，这些等位基因允许分别在表达α-和β-亚基的细胞中合成绿色和红色荧光蛋白。在所有类型的味觉乳头以及软pa和鼻切牙导管的味蕾中检测到荧光信号。但是，报告者的语言表达方式根据舌头的地形而不同。此外，ENaCγ亚基的免疫组织化学显示所有潜在亚基之间都没有重叠。数据表明，阿米洛利对食盐的敏感识别不太可能依赖于由α-，β-和γ亚基形成的经典ENaC，并要求仔细研究通道组成。在所有类型的味觉乳头以及软pa和鼻切牙导管的味蕾中检测到荧光信号。但是，报告者的语言表达方式根据舌头的地形而不同。此外，ENaCγ亚基的免疫组织化学显示所有潜在亚基之间都没有重叠。数据表明，阿米洛利对食盐的敏感识别不太可能依赖于由α-，β-和γ亚基形成的经典ENaC，并要求仔细研究通道组成。在所有类型的味觉乳头以及软pa和鼻切牙导管的味蕾中检测到荧光信号。但是，报告者的语言表达方式根据舌头的地形而不同。此外，ENaCγ亚基的免疫组织化学显示所有潜在亚基之间都没有重叠。数据表明，阿米洛利对食盐的敏感识别不太可能依赖于由α-，β-和γ亚基形成的经典ENaC，并要求仔细研究通道组成。