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The Sexual Differentiation of the Rat Hypothalamus: Organizational and Activational Effects of Sex Steroids

大鼠下丘脑的性别分化：性类固醇的组织和激活作用

基本信息

批准号：
60570077
负责人：
SAKUMA Yasuo
金额：
$ 1.02万
依托单位：
Niigata 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：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60570077/
关键词：
Antidromic action potential Estrogen Hypothalamus Lordosis Midbrain oxytocin Paraventricular nucleus ロードシス.

项目摘要

The ventromedial nucleus of the hypothalamus (VMN) is associated with estrogen-dependent neural regulation of autonomic, neuroendocrine and behavioral functions. VMN cells with axons to the midbrain central gray (CG) have been demonstrated as one of the neural substrates participating in these regulatory processes. The aim of the present series of experiments was to identify and characterize estrogen-sensitive VMN neurons with axons projecting to the CG. Antidromic action potentials were evoked in VMN cells following CG stimulation in the female and male rats, which received various endocrine treatments. Estrogen treatment of adults significantly decreased the antidromic activation threshold and shortened the refractory period in female rats or neonatally castrated male rats, but not in males or females exposed neonatally to testosterone. In the female rats which received no neonatal treatment, estrogen-sensitive neurons were localized in the rostral VMN, had large soma with axonal pro … More jections to the CG via the zona incerta or the supraoptic commissure.A similar type of sexual dimorphism in the estrogen sensitivity existed in the hypothalamic paraventricular nucleus (PVN). Extracellular antidromic potentials were recorded from the PVN of the male and female rat following electrical stimulation of the neurohypophysis. Effects of estrogen-treatment in the castrated animals were investigated after classifying the antidromically identified cells into tonically or phasically-firing, or silent groups according to their patterns of spontaneous discharge. Estrogen significantly decreased the antidromic activation threshold and shortened the refractory period as well as the antidromic spike latency in the tonically-firing cells in the female but not those in the male.Hypothalamic tissue slices containing the PVN were obtained from the ovariectomized female rat. The slices were perfused by aerated artificial cerebrospinal fluid. Acute effects of estrogen were examined on the firing rate as well as on the modulatory responses induced by biogenic amines. Among 51 cells tested, addition of estrogen to the perfusate caused immediate activation in 7 and inhibition in 23 cells, respectively. In a group of estrogen-insensitive cells, simultaneous administration of estrogen with noradrenaline or dopamine resulted in augmented responses to these substances. These data indicated potential estrogen action at the neuronal membrane, to control the activity of specific groups of the hypothalamic cells. Less

下丘脑腹内侧核(VMN)与雌激素依赖的自主神经、神经内分泌和行为功能的调节有关。具有轴突至中脑中央灰质(CG)的VMN细胞已被证明是参与这些调节过程的神经底物之一。这一系列实验的目的是识别和表征对雌激素敏感的VMN神经元，这些神经元的轴突投射到CG。在接受不同内分泌治疗的雌性和雄性大鼠中，CG刺激可在VMN细胞中诱发出逆行动作电位。成年雌激素治疗显著降低了雌性大鼠或新生去势雄性大鼠的逆行激活阈值，缩短了不应期，但对新生大鼠暴露于睾酮的雄性或雌性大鼠无明显影响。未接受新生治疗的雌性大鼠，雌激素敏感神经元定位于吻侧下丘脑室旁核，胞体较大，轴突前…阳性下丘脑室旁核(PVN)在雌激素敏感性方面也存在类似的性别二型性。电刺激神经垂体后，记录雌雄大鼠下丘脑室旁核细胞外逆行电位。在去势动物身上，根据其自发放电的模式，将逆行识别的细胞分为强直或相激组，或静止组，然后研究雌激素治疗的效果。雌激素组雌性大鼠强直电刺激细胞的逆行激活阈值显著降低，不应期缩短，逆行峰潜伏期缩短，而雄性大鼠无明显变化。脑片经充气人工脑脊液灌流。观察雌激素对放电频率和生物胺的调制反应的急性影响。在被测试的51个细胞中，向灌流液中添加雌激素分别导致7个细胞立即激活和23个细胞抑制。在一组雌激素不敏感的细胞中，同时给予雌激素和去甲肾上腺素或多巴胺会导致对这些物质的反应增强。这些数据表明雌激素在神经细胞膜上的潜在作用，以控制特定组的下丘脑细胞的活动。较少