Functional expression of TRPV1 and TRPA1 in rat vestibular ganglia
Functional expression of TRPV1 and TRPA1 in rat vestibular ganglia
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DOI：
10.1016/j.neulet.2013.07.019
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发表时间：
2013-09-27
影响因子：
2.5
通讯作者：
Shimada, Shoichi
中科院分区：
文献类型：
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作者：
Kamakura, Takefumi;Ishida, Yusuke;Shimada, Shoichi
TRPV1和TRPA1都是非选择性阳离子通道。它们在背根神经节(DRG)和三叉神经节(TG)等感觉神经元中共同表达，并相互作用，参与伤害性感受，被伤害性刺激激活。TRPV1在前庭神经节(VG)神经元中的免疫组织化学定位已有报道。尽管TRPA1和TRPV1在DRG和TG神经元中共表达，但TRPA1通道是否在VG神经元中表达尚不清楚。此外，目前尚不清楚TRPV1和TRPA1通道在VG神经元中是否具有功能。我们用RT-PCR、原位杂交、免疫组织化学和钙离子成像等方法研究了TRPV1和TRPA1在大鼠VG神经元中的表达。从大鼠VG神经元的mRNA中扩增出TRPV1和TRPA1的RT-PCR产物。原位杂交结果显示，大多数VG神经元表达TRPV1和TRPA1mRNA。免疫组织化学实验证实TRPV1蛋白表达。在钙离子成像实验中，TRPV1激动剂辣椒素可引起原代培养的大鼠VG神经元细胞内钙离子浓度([Ca~(2+)](I))显著升高，该作用可被TRPV1特异性拮抗剂Capsazepine几乎完全阻断。TRPA1激动剂肉桂醛也可引起[Ca~(2+)](I)升高，此作用可被TRPA1特异性拮抗剂HC030031完全抑制。此外，在一些VG神经元中，辣椒素和肉桂醛均可引起同一神经元内[Ca~(2+)](I)的升高。综上所述，我们的组织学和生理学研究表明，TRPV1和TRPA1在VG神经元中表达。提示VG神经元中的TRPV1和TRPA1可能参与了前庭功能和/或眩晕等功能障碍。(C)2013爱思唯尔爱尔兰有限公司。保留所有权利。
Both TRPV1 and TRPA1 are non-selective cation channels. They are co-expressed, and interact in sensory neurons such as dorsal root ganglia (DRG) and trigeminal ganglia (TG), and are involved in nociception, being activated by nociceptive stimuli. Immunohistological localization of TRPV1 in vestibular ganglion (VG) neurons has been reported. Although TRPA1 is co-expressed with TRPV1 in DRG and TG neurons, it is unclear whether TRPA1 channels are expressed in VG neurons. Moreover, it is unknown whether TRPV1 and TRPA1 channels are functional in VG neurons. We investigated the expression of TRPV1 and TRPA1 in rat VG neurons by RT-PCR, in situ hybridization, immunohistochemistry, and Ca2+ imaging experiments. Both TRPV1 and TRPA1 RT-PCR products were amplified from the mRNA of rat VG neurons. In situ hybridization experiments showed TRPV1 and TRPA1 mRNA expression in the majority of VG neurons. Immunohistochemistry experiments confirmed TRPV1 protein expression. In Ca2+ imaging experiments, capsaicin, a TRPV1 agonist, induced a significant increase in intracellular calcium ion concentration ([Ca2+](i)) in rat primary cultured VG neurons, which was almost completely blocked by capsazepine, a TRPV1-specific antagonist. Cinnamaldehyde, a TRPA1 agonist, also caused an increase in [Ca2+](i), which was completely inhibited by HC030031, a TRPA1-specific antagonist. Moreover, in some VG neurons, a [Ca2+](i); increase was evoked by both capsaicin and cinnamaldehyde in the same neuron. In summary, our histological and physiological studies reveal that TRPV1 and TRPA1 are expressed in VG neurons. It is suggested that TRPV1 and TRPA1 in VG neurons might participate in vestibular function and/or dysfunction such as vertigo. (C) 2013 Elsevier Ireland Ltd. All rights reserved.