Expression of ATP-gated P2X3 receptors in rat gustatory papillae and taste buds
Expression of ATP-gated P2X3 receptors in rat gustatory papillae and taste buds
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DOI：
10.1679/aohc.69.281
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发表时间：
2006-12-01
影响因子：
--
通讯作者：
Toyoshima, Kuniaki
中科院分区：
文献类型：
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作者：
Kataoka, Shinji;Toyono, Takashi;Toyoshima, Kuniaki
最近发现ATP和其他细胞外核苷酸在信号转导中起重要作用。ATP通过P2 X受体介导兴奋性信号传导。P2 X（3）是其亚型之一，是一种膜配体门控离子通道，在外周感觉神经元中强烈表达。采用免疫组织化学方法观察大鼠味觉乳头和软腭中P2 X（3）受体阳性神经纤维的分布。我们发现，荧光ATP标记奎纳克林染色的味蕾细胞亚群。许多神经纤维支配味蕾强烈免疫染色与P2 X（3）受体抗体。这些神经纤维在胚芽内细胞中上升，并终止于味觉孔下方。为了检测P2 X（3）受体是否参与味蕾内的信号调节，我们使用荧光双染色来分析P2 X（3）受体的分布及其与α-味觉蛋白免疫阳性味觉受体细胞的关系。许多表达P2 X（3）受体免疫反应性的曲张神经纤维与α-味蛋白免疫阳性味觉受体细胞纠缠在一起，并在味孔下方紧密结束。在菌状乳头中，观察到同时表达P2 X（3）受体和PGP 9.5的神经纤维。相比之下，只有PGP 9.5免疫反应阳性神经纤维被确认丝状乳头。这些结果提示P2 X（3）受体可能参与味蕾内的味觉传递途径。ATP可以作为神经递质、共递质或神经调质在P2 X（3）受体上产生激活味觉神经纤维。
It has recently become evident that ATP and other extracellular nucleotides could play an important role in signal transductions. ATP mediates excitatory signaling by means of P2X receptors. P2X(3), one of its subtypes, a membrane ligand-gated ion channel, is strongly expressed in peripheral sensory neurons. The aim of the present study was to examine the distribution of nerve fibers expressing P2X(3) receptors in taste buds in the gustatory papillae and soft palate of rats by immunohistochemistry. We found that the fluorescence ATP marker quinacrine stained subsets of taste bud cells. Numerous nerve fibers innervating taste buds were intensely immunostained with the P2X(3) receptor antibody. These nerve fibers ascended among intragemmal cells and terminated just below the taste pores. In order to examine whether P2X(3) receptors are involved in signal modulation within taste buds, we used fluorescent double stainings to analyze the distribution of P2X(3) receptors and their relationship to alpha-gustducin immunopositive taste receptor cells. Many varicose nerve fibers expressing P2X(3) receptor-immunoreactivities were entangled with alpha-gustducin immunopositive taste receptor cells and ended closely below the taste pores. In fungiform papillae, nerve fibers expressing both P2X(3) receptors and PGP 9.5 were observed. In contrast, only PGP 9.5 immunoreactive nerve fibers were recognized in filiform papillae. These results suggest that P2X(3) receptors might be involved in taste transmission pathways within taste buds. ATP may act as a neurotransmitter, co-transmitter, or neuromodulator at P2X(3) receptors to generate activating gustatory nerve fibers.