5-HT₃ receptor expression in the mouse vestibular ganglion

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• 作者：Yasumitsu Takimoto^a ; ^b ; Yusuke Ishida^b ; ^{ishida@anat1.med.osaka-u.ac.jp" class="auth_mail} ; Yukiko Nakamura^b ; Takefumi Kamakura^a ; ^b ; Takahiro Yamada^b ; Makoto Kondo^b ; Tadashi Kitahara^a ; Atsuhiko Uno^a ; Takao Imai^a ; Arata Horii^a ; Suzuyo Okazaki^a ; Suetaka Nishiike^a ; Hidenori Inohara^a ; Shoichi Shimada^b
• 关键词：5-HT ; HTR3 ; Cochlea ; Spiral ganglion ; Inner ear ; In situ hybridization
• 刊名：Brain Research
• 出版年：4 April, 2014
• 年：2014
• 卷：1557
• 期：Complete
• 页码：74-82
• 全文大小：5406 K

文摘

The 5-hydroxytryptamine type 3 (5-HT₃) receptor is a ligand-gated ion channel and a member of the Cys-loop family of receptors. Previous studies have shown 5-HT₃ receptor expression in various neural cells of the central and peripheral nervous systems. Although the function and distribution of the 5-HT₃ receptor has been well established, its role in the inner ear is still poorly understood. Moreover, no study has yet determined its localization and function in the peripheral vestibular nervous system. In the present study, we reveal mRNA expression of both 5-HT_3A and 5-HT_3B receptor subunits in the mouse vestibular ganglion (VG) by RT-PCR and in situ hybridization (ISH). We also show by ISH that 5-HT₃ receptor mRNA is only expressed in the VG (superior and inferior division) in the peripheral vestibular nervous system. Moreover, we performed Ca²⁺ imaging to determine whether functional 5-HT₃ receptors are present in the mouse VG, using a selective 5-HT₃ receptor agonist, SR57227A. In wild mice, 32% of VG neurons responded to the agonist, whereas there was no response in 5-HT_3A receptor knockout mice. These results indicate that VG cells express functional 5-HT₃ receptor channels and might play a modulatory role in the peripheral vestibular nervous system.