Electrophysiological identification of LHRH neurons that are involved in the LH surge induced by positive feedback action of estrogen.
| Project/Area Number |
02670071
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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 | Yokohama City University |
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Principal Investigator |
TANAKA Fukuko Yokohama City University School of Medicine, Professor, 医学部, 教授 (40046066)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Yutaka Yokohama City University School of Medicine, Instructor, 医学部, 助手 (90194050)
HIRUMA Hiromi Yokohama City University School of Medicine, Instructor, 医学部, 助手 (10238397)
FUNABASHI Toshiya Yokohama City University School of Medicine, Instructor, 医学部, 助手 (70229102)
NISHIHARA Masugi Yokohama City University School of Medicine, Instructor, 医学部, 助手 (90145673)
ARITA Jun Yokohama City University School of Medicine, Associate Professor, 医学部, 助教授 (80128587)
橋本 隆平 横浜市立大学, 医学部, 助手 (70189512)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Multiunit activity / LHRH neurons / Median eminence of the hypothalamus / LH surge / Estrogen / Positive feedback / Opioid peptides / 多ニュ-ロン発射活動 / LHRHニュ-ロン / LH分泌 / フィ-ドバック / オピオイドニュ-ロン / GABAニュ-ロン / 内側視索前野 / プロゲステロン / ラット |
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| Research Abstract |
We have raised the hypothesis that the LHRH neurons that are involved in the phasic release of LH (LH surge) induced by positive feedback action of estrogen are different from those that are involved in the pulsatile release of LH occurring in the ovariectomized conditions. The present study was undertaken to investigate this hypothesis further using the multiunit activity (MUA)recording technique. The results are as follows.
1. The LHRH neurons showing MUA which increases intermittently in association with LH pulses are involved in the basal release of LH controlled by negative feedback effect of estrogen. We have called these LHRH neurons Type I. The negative feedback effect of estrogen to these neurons are mediated by opioid peptidergic neurons. Further, the intermittent, cyclic firing of these Type I neurons is pentobarbital sensitive.
2. We called those LHRH neurons that are involved in phasic LH release (LH surge) Type II. Those neurons are different from Type I in some aspects as follows : (1) These LHRH neurons do not show MUA which increases intermittently in association with LH pulses in ovariectomized rats. (2) The mechanism that involves Type II LHRH neurons and acts to control LH surge in response to positive feedback effects of estrogen dose not involve opioid peptidergic neurons, but (3) is sensitive to pentobarbital.
In conclusion, the results have suggested that LHRH neurons in the CNS have two functional subtypes, arbitrarily called Type I and Type II. The electrical activity of Type II neurons could not be recorded, even by the MUA technique. It seems necessary to place the electrodes at the more frontal site.
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Report
(3 results)
Research Products
(8 results)
