2004 Fiscal Year Final Research Report Summary
Auditory circuits are visualized in the inferior colliculus of the transgenic mouse
| Project/Area Number |
15500234
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nerve anatomy/Neuropathology
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| Research Institution | Shiga University of Medical Science |
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Principal Investigator |
KUDO Motoi Shiga University of Medical Science, School of Medicine, 医学部, 教授 (80108141)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Kiyoshi Shiga University of Medical Science, School of Medicine, 医学部, 助教授 (40215083)
NAKAMURA Takaaki Shiga University of Medical Science, School of Medicine, 医学部, 助手 (30314157)
TAKI Kousuke Shiga University of Medical Science, School of Medicine, 医学部, 助手 (20359772)
NODA Masaharu Shiga University of Medical Science, National Institute for Basic Biology, 基礎生物学研究所, 教授 (60172798)
WATANABE Eiji Shiga University of Medical Science, National Institute for Basic Biology, 基礎生物学研究所, 助教授 (30250252)
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| Project Period (FY) |
2003 – 2004
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| Keywords | auditory / inferior colliculus / transgenic mouse / nociceptin / GABA / electroporation / neuronal circuit / choleratoxin |
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| Research Abstract |
In lines of transgenic mouse, Brn3b, which have been established by Drs. Noda and Watanabe in National Institute for Basic Biology, the auditory pathways are specifically visualized genetically by expressing beta-galactosidase. Along with the guideline of experimental animal use in our institute, we maintain the mouse line for the anatomical developmental study. X-gal staining was performed according to Watanabe (2000). The results show that beta-galactosidase was stained best in the neonatal stages (P0-P3). The stain in the inferior colliculus(IC) and the superior olive was the strongest, that in the lateral lemniscus and the cochlear nuclei was modest, and that in the medial geniculate body was not so strong but very clear. Axons in these auditory structures were always successfully stained at all stages, although it was hard to discern the cell soma and the neuropil in newborns. To characterize nociceptin-expressing neurons in the IC, we further made a series of experiments in developing rats. Choleratoxin B subunit(CtxB) gene was connected with prepronociceptin promotor region 5kb long upstream to the exon I and designed to be expressed under the control of prepronociceptin promotor. This artificial DNA was injected into the IC, and an electric field was administrated. Some of the IC neurons were successfully stained with anti-CtxB antibody. These neurons were distributed not only in the external nucleus and the dorsal cortex but also the central nucleus. In the double immunofluorescent paradigm, almost all the CtxB immunoreactive neurons had GABA and nociceptin immunoreactivity. We thus successfully visualized nociceptin neurons in the IC. The evidence substantiates crucial role of nociceptin in auditory center, offering new opportunities in the treatment of the central hearing disorders such as tinnitus, audiogenic seizures and age-related hearing loss.
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