G-protein-dependent and -independent pathways in denatonium signal transduction
G-protein-dependent and -independent pathways in denatonium signal transduction
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DOI：
10.1271/bbb.69.1643
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发表时间：
2005-09-01
影响因子：
1.6
通讯作者：
Hayashi, Y
中科院分区：
文献类型：
--
作者：
Sawano, S;Seto, E;Hayashi, Y
为了阐明G蛋白在变性信号转导中的作用，我们对分离的小鼠味觉细胞进行了全细胞膜片钳分析。应用G蛋白抑制剂GDPβ-S，观察到两种不同的反应。其中一个对变性的反应被GDPbeta-S(G蛋白依赖)降低，而另一个不受影响(G蛋白非依赖性)。通过G蛋白同时抑制磷脂酶Cβ(2)和磷酸二酯酶途径，也观察到了这些不同的模式。这些数据提示了变性的双重、G蛋白依赖和非独立的机制。此外，单独抑制磷脂酶Cβ(2)或磷酸二酯酶途径并不能减弱变性反应，这意味着这两条途径都参与了G蛋白依赖的转导。在不依赖G蛋白的细胞中，这种反应被细胞内储存的钙离子耗尽所消除。这些结果表明，细胞内钙离子的释放是一个重要的因素。我们的数据证明了哺乳动物味觉细胞中变性的多种转导途径。
To clarify the involvement of G protein in denatonium signal transduction, we carried out a whole-cell patch-clamp analysis with isolated taste cells in mice. Two different responses were observed by applying GDP-beta-S, a G-protein inhibitor. One response to denatonium was reduced by GDP-beta-S (G-protein-dependent), whereas the other was not affected (G-protein-independent). These different patterns were also observed by concurrently inhibiting the phospholipase C beta(2) and phosphodiesterase pathways via G protein. These data suggest dual, G-protein-dependent and -independent mechanisms for denatonium. Moreover, the denatonium responses were not attenuated by singly inhibiting the phospholipase C beta(2) or phosphodiesterase pathway, implying that both pathways were involved in G-protein-dependent transduction. In the G-protein-independent cells, the response was abolished by the depletion of calcium ions within the intracellular store. These results suggest that Ca2+ release from the intracellular store is an important factor. Our data demonstrate multiple transduction pathways for denatonium in mammalian taste cells.