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Electrophysiological identification of LHRH neurons that are involved in the LH surge induced by positive feedback action of estrogen.

参与雌激素正反馈作用诱导的 LH 激增的 LHRH 神经元的电生理学鉴定。

基本信息

批准号：
02670071
负责人：
TANAKA Fukuko
金额：
$ 1.54万
依托单位：
Yokohama City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

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.

我们提出了这样的假设，即参与由雌激素的正反馈作用诱导的LH的阶段性释放（LH峰）的LHRH神经元不同于那些参与发生在卵巢切除条件下的LH的脉冲式释放的LHRH神经元。本研究采用多单位活动（MUA）记录技术进一步探讨这一假设。研究结果如下：1.显示MUA的LHRH神经元与LH脉冲间歇性相关地增加，参与了由雌激素负反馈效应控制的LH基础释放。我们称这些LHRH神经元为I型。雌激素对这些神经元的负反馈作用是通过阿片肽能神经元介导的。此外，这些I型神经元的间歇性周期性放电是戊巴比妥敏感的。我们将参与阶段性LH释放（LH峰）的LHRH神经元称为II型。这些神经元与Ⅰ型神经元的不同之处在于：（1）在去卵巢大鼠中，这些LHRH神经元不显示与LH脉冲相关的间歇性MUA增加。(2)Ⅱ型LHRH神经元参与雌激素的正反馈作用，控制LH峰的机制不涉及阿片肽能神经元，但（3）对戊巴比妥敏感。总之，结果表明，中枢神经系统中的LHRH神经元有两种功能亚型，任意称为Ⅰ型和Ⅱ型。II型神经元的电活动不能被记录，即使通过MUA技术。似乎有必要将电极放置在更正面的部位。