| Project/Area Number |
10670063
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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 |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Hyogo University of Teacher Education |
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Principal Investigator |
MATSUMURA Kyoko Imai Hyogo University of Teacher Education, Dept. of Life and Health Science, Professor, 学校教育学部, 教授 (40173877)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yasuyoshi Osaka Bioscience Institute, 3Dept. of Neuroscience, Senior Manager, 第3部門, 部長 (40144399)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | pregnant / rat / fever / prostaglandin EィイD22ィエD2 / cyclooxygenese / interleukin-1β |
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| Research Abstract |
We investigated the mechanism of suppression of fever in full-term pregnant rats. Injection of prostaglandin EィイD22ィエD2 (PGEィイD22ィエD2) into the preoptic area in these rats evoked fever suggesting that PGEィイD22ィエD2 sensitivity and the effectors for thermogenesis were intact. However, the increase in PGEィイD22ィエD2 in the cerebrospinal fluid after intraperitoneal injection of lipopolysaccharide (LPS) was significantly reduced in full-term pregnant rats as compared to virgin rats. The number of LPS-induced cyclooxygenese-2-positive cells in the brain of full-term pregnant rats is due to the suppression of PGEィイD22ィエD2 synthesis.
Furthermore, we investigated whether the upstream of the arachidonic acid cascade, I.e., production of pyrogenic cytokines, is altered in the full-term pregnant rats. Five hours after intraperitoneal injection of lipopolysaccharide (LPS, 100 μg/kg) or saline, rat brains were processed for interleukin-1β (IL-1β) immunohistochemistry. After saline injection, no IL-1β-positive cells were found in the brains of either virgin rats or pregnant ones. In the virgin rats injected with LPS, a certain type of cells in the circumventricular organs were intensely stained for IL-1β. On the other hand, in the full-term pregnant rats injected with LPS, there was almost no IL-1β-positive cell. These results suggest that suppressed production of endogenous pyrogens is involved in the decreased fever response in full-term pregnancy.
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