| Project/Area Number |
17591936
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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 |
Functional basic dentistry
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| Research Institution | Okayama University |
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Principal Investigator |
KOBASHI Motoi Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Associate Professor, 大学院医歯薬学総合研究科, 助教授 (80161967)
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| Co-Investigator(Kenkyū-buntansha) |
TSUKAMOTO Goichi Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Assistant Professor, 大学院医歯薬学総合研究科, 助手 (40263610)
MATSUO Ryuji Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Professor, 大学院医歯薬学総合研究科, 教授 (30157268)
MITOH Yoshihiro Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Assistant Professor, 大学院医歯薬学総合研究科, 助手 (20240872)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | ghrelin / neuropeptide Y / melanin-concentrating hormone / stomach / gastric relaxation / palatability / medulla / vagus / Y1受容体 / (D-Lys3)GHRP-6 |
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| Research Abstract |
The functional correlation between palatability and gastric motility induced by appetite-enhancing peptides were investigated in this study. The effects of neuropeptide Y (NPY) on motility of the proximal stomach were examined in anaesthetized rats. The administration of NPY into the 4th ventricle induced relaxation of the proximal stomach in a dose-dependent manner. The administrations of Y1 receptor (Y1R) agonist induced relaxation potently rather than those of NPY. The microinjections of Y1R agonist into the caudal part of the dorsal vagal complex (c-DVC) induced relaxation of the proximal stomach. The administration of NPY into the 4th ventricle did not induce relaxation after bilateral injection of Y1R antagonist into the c-DVC. These results revealed that NPY induced the relaxation in the proximal stomach via Y1R situated in the DVC. The effect of ghrelin on motility of the proximal stomach was also examined. The administration of ghrelin into the fourth ventricle induced relaxat
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ion of the proximal stomach in a dose-dependent manner. Simultaneous administration of ghrelin and GHS-R antagonist did not induce significant change in IGP. Microinjections of ghrelin into the c-DVC induced relaxation of the proximal stomach. These results indicate that ghrelin induces the relaxation of the proximal stomach via the GHS-R situated in the DVC as well as NPY. These results strongly suggest that the appetite-enhancing peptide facilitate reservoir function of the stomach to accommodate body to overconsumption elicited by the appetite-enhancing neuropeptides. However, the administration of the other appetite-enhancing peptides, melanin-concentrating hormone (MCH), did not induce gastric response. Intracerebroventricular (ICV) administrations of orexin, MCH and NPY increased the intake of saccharin. Drinking of saccharin in turn elevated the mRNA levels of orexin and NPY, but not MCH. Pre-treatments of naloxone, an opioid antagonist, blocked the orexigenic effects of orexin and NPY. These results suggest that the overconsumption promoted by sweet and palatable tastes is attributed to the activation of orexigenic neuropeptides, such as orexin and NPY, and a downstream opioid system together with enhanced digestive functions. Less
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