Differential expression of RNA and protein of the three pore-forming subunits of the amiloride-sensitive epithelial sodium channel in taste buds of the rat
Differential expression of RNA and protein of the three pore-forming subunits of the amiloride-sensitive epithelial sodium channel in taste buds of the rat
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DOI：
10.1177/002215549904700106
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发表时间：
1999-01-01
影响因子：
3.2
通讯作者：
Lindemann, B
中科院分区：
文献类型：
--
作者：
Kretz, O;Barbry, P;Lindemann, B
来自大鼠前舌的盐味信号可能是通过位于味觉细胞顶端极的上皮钠通道（ENaCs）转导的。在低mu - M浓度下，这些信号被粘膜氨酰胺阻断。相比之下，大鼠的谷状乳头并不能产生可阻断的盐味。采用两种方法对钠平衡大鼠前后舌内ENaC的三个亚基进行了探测。(a)针对ENaC亚基和amiloride结合位点抗体的免疫组化。在舌头前部，味蕾和舌上皮中存在α -亚基、β -亚基和γ -亚基的反应性，在舌头后部的腭状乳头中，α -亚基和阿米洛利结合位点的反应性很容易被证明，而β -亚基，尤其是γ -亚基的反应性比舌头前部弱。(b)采用RT-PCR技术检测ENaC亚基mRNA的存在。在分离的舌前味蕾中，发现了所有三个亚基的mRNA，而在分离的腭乳头味蕾中，只有α亚基的mRNA很容易检测到。而β亚基和γ亚基则少得多。这三个亚基的RNA仅在舌前味蕾中丰富。因此，伸长味觉细胞亚群确实表达ENaC，但亚单位的转录和表达存在区域差异。正如功能研究表明的那样，区域差异表明，需要所有三个亚基的阿米洛利盐敏感味觉存在于大鼠的舌头前部而不是后部。
Salt taste signals from the rat anterior tongue are probably transduced via epithelial sodium channels (ENaCs) residing in the apical cellular pole of taste cells. The signals are blocked by mucosal amiloride in low mu M concentrations. In contrast, the rat vallate papilla does not contribute to amiloride-blockable salt taste. Two approaches were used to probe for the three subunits of ENaC in the anterior and posterior tongue of the rats in sodium balance. (a) Immunohistochemistry with antibodies against ENaC subunits and against amiloride binding sites. In the anterior tongue, reactivity for alpha-, beta-, and gamma-subunits was present in taste buds and lingual epithelium, in the posterior tongue vallate papilla, reactivity for alpha-subunit and for amiloride binding sites was easily demonstrable, whereas that for beta-subunit and especially for gamma-subunit was weaker than in the anterior tongue. (b) RT-PCR techniques were used to probe for the presence of ENaC subunit mRNA. In isolated taste buds of the anterior tongue, mRNA of all three subunits was found, whereas in isolated taste buds of the vallate papilla only mRNA of the alpha-subunit was easily detectable. That of beta- and gamma-subunits was much less abundant. RNA of all three subunits was abundant only in taste buds of the anterior tongue. Therefore, subsets of elongated taste cells do express ENaC, but regional differences exist in the transcription and expression of subunits. The regional differences suggest that amiloride-sensitive salt taste, which requires all three subunits, is present in the anterior but not the posterior tongue of rats, as functional studies indicate.