1995 Fiscal Year Final Research Report Summary
Serotonergic regulation to the suprachiasmatic nuleus
| Project/Area Number |
06670968
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Psychiatric science
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| Research Institution | Kyoto Prefectural University of Medicine |
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Principal Investigator |
KAWAKAMI Fumio Dept.of Psychiatry, Kyoto Prefectural University of Medicine, assistant, 医学部, 助手 (60186062)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMURA Hitoshi Dept.of Anatomy, Kyoto Prefectural University of Medicine, associate professor, 医学部, 助教授 (60158813)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Suprachiasmatic nucleus / Vasoactive intestinal peptide / Serotonin / In situ hybridization |
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| Research Abstract |
Photic stimulus and serotonin (5-hydroxytryptamine : 5-HT) are two factors known to regulate vasoactive intestinal peptide (VIP) synthesis in the suprachiasmatic nucleus (SCN). To explore the role of 5-HT in the photic stimulus-induced change in VIP synthesis, we investigated the changes in level of VIP mRNA under a 12h light-12h dark cycle following depletion of 5-HT by intraperitoneal administration of p-chloropheylalanine (PCPA) methyl ester (200mg/kg, concentration) for three successive days. To estimate VIP mRNA expression, we performed in situ hybridization using imaging plates combined with microcomputer-based imaging analysis. In light-phase, total signals of VIP mRNA from the PCPA-treated rats showed a significant decrease compared with those from the saline-treated control rats. However, in dark-phase, there were no significant decreases between the PCPA-treated rats and the saline-control rats. The present results strongly suggest that 5-HT neuronal inputs to the SCN interfere with the effect of photic stimulus on VIP synthesis at the mRNA level.
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