Among the 5 taste qualities, salt is the least understood. The receptors, their expression pattern in taste cells, and the transduction mechanisms for salt taste are still unclear. Previous studies have suggested that low concentrations of NaCl are detected by the amiloride-sensitive epithelial Na+ channel (ENaC), which in other systems requires assembly of 3 homologous subunits (α, β, and γ) to form a functional channel. However, a new study from Lossow and colleagues, published in this issue of Chemical Senses, challenges that hypothesis by examining expression levels of the 3 ENaC subunits in individual taste cells using gene-targeted mice in combination with immunohistochemistry and in situ hybridization. Results show a lack of colocalization of ENaC subunits in taste cells as well as expression of subunits in taste cells that show no amiloride sensitivity. These new results question the molecular identity of the amiloride-sensitive Na+ conductance in taste cells.

中文翻译：

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味觉细胞中对Amiloride敏感的Na +通道真的是ENaC吗？

在5种口味品质中，对盐的了解最少。受体，它们在味觉细胞中的表达模式以及盐味的转导机制仍不清楚。先前的研究表明，阿米洛利敏感的上皮Na +通道（ENaC）可检测到低浓度的NaCl，在其他系统中，这需要组装3个同源亚基（α，β和γ）才能形成功能性通道。然而，Lossow及其同事发表于本期《化学常识》上的一项新研究通过使用靶向基因的小鼠结合免疫组织化学和原位杂交技术检查单个味觉细胞中3个ENaC亚基的表达水平，挑战了这一假设。结果表明，味觉细胞中缺乏ENaC亚基的共定位，并且味觉细胞中亚基的表达没有阿米洛利敏感性。这些新结果质疑味觉细胞中阿米洛利敏感的Na +电导的分子同一性。