| Project/Area Number |
61570084
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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 |
環境生理学(含体力医学･栄養生理学)
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| Research Institution | Niigata University |
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Principal Investigator |
AKAISHI Takao Niigata University, School of Medicine, Lecturer, 医学部, 講師 (70018951)
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| Co-Investigator(Kenkyū-buntansha) |
SAKUMA Yasuo Niigata University, School of Medicine, associate profesor, 医学部, 助教授 (70094307)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1987: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Osmoreceptor / Estrogen / vasopressin / upraoptic nucleus / in vitro / ラット / 浸透圧受容器 / 室傍核 / 視索前野 / アンジオテンシン |
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| Research Abstract |
Our previous studies have shown that estrogen affects the electrical activity of the oxytocin-producing cells in the female hypothalamus. Contrary to this, the vasopressin-producing cells are not affected at all in their activity by estrogen treatment. However, estrogen was confirmed to decrease the plasma osmorality and drinking activity in our preliminary study. These facts suggest the possibility that estrogen may affect the basal firing activity of vasopressin-producing cells or the osmoreceptors in the central nervous system. Thus, the present project was planed to determine the centrally mediated action of estrogen on the sensitivity of the osmoreceptors and the activity of vasopressin-producing cells. Ovariectomized Wistar rats with or without estrogen-treatment were used in this project. Immediately after decapitation the brain was quickly removed and slice (300-400 <micrn>m). The supraoptic nuclei (SON) were further isolated from surroundings with the blade. During the SON were perfused in different osmolar (295 and 320 mosml/l) artificial CSF, single unit discharges of vasopressin-producing cells were recorded. In the 295 mosmol/l medium, the mean firing rate of units in the estrogen-treated subjects was significantly higher than that in the control. The increased ratio in mean firing rate in estrogenized rats were similar to the control, when perfused artificial-CSF was changed from 295 to 329 mosmol/l. These data indicate that (1) the firing activity of vasopressin-producing cells in estrogenized female rats is set at higher level than the control, (2) estrogen has no-effects on osmosensitivity itself of the vasopressin-producing cells.
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