Neuronal expression of bitter taste receptors and downstream signaling molecules in the rat brainstem
Neuronal expression of bitter taste receptors and downstream signaling molecules in the rat brainstem
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DOI：
10.1016/j.brainres.2012.07.038
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发表时间：
2012-09-26
期刊：
影响因子：
2.9
通讯作者：
Jayam-Trouth, Annapurni
中科院分区：
文献类型：
--
作者：
Dehkordi, Ozra;Rose, Jed E.;Jayam-Trouth, Annapurni
以前的研究表明，味觉传导途径的分子可能作为呼吸道和胃肠道化学感受细胞的生化标志物。在这项研究中，我们测试了一个假设，即脑干神经元含有类似于味蕾的信号分子，可以感知脑细胞外液的化学成分。我们使用逆转录聚合酶链反应（RT-PCR），蛋白质印迹和免疫组织化学技术来评估不同的味觉反应2型味觉受体（T2 R），其相关的G-蛋白α-gustducin，下游信号分子磷脂酶C亚型β 2（PLC-β 2）和瞬时受体电位melastatin 5（TRPM 5）在大鼠脑干的存在。RT-PCR证实延髓中存在编码α-味蛋白、PLC-β 2、TRPM 5和rT 2 R1的mRNA，而不存在编码rT 2 R16、rT 2 R26和rT 2 R38的mRNA。蛋白质印迹法证实了大鼠脑干中α-味蛋白在蛋白质水平上的存在。免疫组织化学鉴定了在多个心肺和CO2/H+化学感受部位表达α-味蛋白和PLC-β 2的细胞，包括延髓腹侧头端、面部、锥体旁、孤束、舌下神经和中缝核。在延髓中缝，α-gustducin和PLC-β 2共定位与色氨酸羟化酶（TPH）免疫反应性神经元，其中一个子集具有呼吸CO2/H+化学敏感性的亚群。脑干中T2 R1基因和苦味转导途径的其他基因和蛋白质的存在意味着味觉受体及其效应分子除了味觉功能之外的其他功能。(c)2012爱思唯尔有限公司版权所有。
Previous studies have shown that molecules of the taste transduction pathway may serve as biochemical markers for chemoreceptive cells in respiratory and gastrointestinal tracts. In this study, we tested the hypothesis that brainstem neurons contain signaling molecules similar to those in taste buds which may sense the chemical composition of brain extracellular fluids. We used the revere transcription polymerase chain reaction (RT-PCR), Western blot and immunohistochemical techniques to evaluate presence of different bitter-responsive type 2 taste receptors (T2Rs), their associated G-protein alpha-gustducin, the downstream signaling molecules phpspholipase C isoform beta 2 (PLC-beta 2) and transient receptor potential melastatin 5 (TRPM5) in the brainstem of rats. RT-PCR confirmed the mRNA coding for alpha-gustducin, PLC-beta 2, TRPM5 and rT2R1 but not that of rT2R16, rT2R26 and rT2R38 in the medulla oblongata. Western blotting confirmed the presence of alpha-gustducin at the protein level in rat brainstem. Immunohistochemistry identified cells expressing a-gustducin and PLC-beta 2 at multiple cardiorespiratory and CO2/H+ chemosensory sites, including rostral ventral medulla, facial, parapyramidal, solitary tract, hypoglossal and raphe nuclei. In the medullary raphe, alpha-gustducin and PLC-beta 2 were colocalized with a subpopulation of tryptophan hydroxylase (TPH)-immunoreactive serotonergic neurons, a subset of which has respiratory CO2/H+ chemosensitivity. Presence of the T2R1 gene and other genes and proteins of the bitter taste transduction pathway in the brainstem implies additional functions for taste receptors and their effector molecules apart from their gustatory function. (c) 2012 Elsevier B.V. All rights reserved.