2003 Fiscal Year Final Research Report Summary
Descending projections of GABA and 5-HT neurons from medullary raphe nuclei to the phrenic nuleus.
| Project/Area Number |
13680901
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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 |
神経・脳内生理学
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| Research Institution | Sapporo Medical University |
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Principal Investigator |
AOKI Mamoru Sapporo Medical University, School of Medicine, Professor, 医学部, 教授 (50001871)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUYAMA Kiyoji Sapporo Medical University, School of Medicine, Associate Professor, 医学部, 助教授 (40209664)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Raphe magunus / Raphe pallidus / GABA / 5-HT / Respiratory movement / Pherenic muscles / Cat |
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| Research Abstract |
Projections of γ-aminobutyric acid(GABA) and serotonin(5-HT) neurons in the medullary raphe nuclei to the phrenic motor nucleus was studied using a combined method of retrograde WGA-HRP(wheat germ agglutinin-conjugated horseradish peroxidase) labeling and anti-GAD(glutamic acid decarboxylase) or anti-5-HT immunostaining. Localized injection of WGA-HRP was made into the phrenic motor nucleus in C_5-C_6 segments in six cats. After a post-injection survival period of 72 hrs, the colchicine treated animals were perfused and serial transverse sections(50μm thick) of the brainstem were made. The sections were first processed for HRP reaction with TMB-Co-DAB method and further processed for anti-GAD or anti-5-HT immunostaining with anti-GAD or anti-5-HT primary antibody. The sections were further incubated in FITC conjugated secondary antibody.
GAD immunopositive and HRP double-labeled(GAD-HRP double-labeled) neurons were observed in several respiratory related structures including the raphe magnus(RM), the ventromedial area of the retrofacial nucleus(Bot.C), the Kolliker-Fuse(KF) nucleus and the rostral ventrolateral medulla(RVLM), whereas 5-HT immunopositive and HRP double-labeled(5-HT-HRP double labeled) neurons were restricted mainly in the nucleus raphe pallidus(RP) and RVLM. These findings may indicate the GABAergic neurons in the RM,KF and RVLM, and 5-HT neurons in the RP and RVLM send monosynaptic axonal projections to the phrenic motor nucleus, it is suggested that GABAergic and 5-HT neurons have inhibitory and excitatory controls respectively, on phrenic motoneuron excitability.
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