IDENTIFYING AND CHARACTERIZING BRAIN GNRH RECEPTORS

拟议研究的总体目标是进一步表征 促性腺激素释放激素（GnRH）的脑内作用部位， 确定调节GnRH神经元系统的神经递质 在老鼠。具体而言，我们建议： 1.用免疫组织化学和“原位”杂交鉴定 大脑中表达GnRH受体的细胞。我们最近生成了一个 一组针对合成肽序列的特异性抗体， 垂体促性腺激素释放激素的胞内和胞外域的一部分 受体蛋白，我们已经开发了cRNA探针，以确定网站 促性腺激素释放激素受体在大脑中的合成。我们现在建议， 确定：a. GnRH受体产生神经元的位置; B.的 促性腺激素释放激素受体合成中神经递质的特性 神经元和是否GnRH受体mRNA的相对量的变化， 对雌二醇的反应。 2.确定GnRH介导的对海马神经元的作用。期间 上一个融资期，我们确定并描述了结构/约束力 脑GnRH受体的关系，并表明GnRH引起 某些海马神经元中c-fos的瞬时诱导。我们提出 现在来确定GnRH是否会引起神经活性信使的释放， 以及这种效应是否受到性腺激素的调节 类固醇. 3.识别第二信使系统，将GnRH信号传递给 海马靶神经元的内部我们将重点关注 Ca ~（++）内流和再分布以及对磷酸肌醇水解的影响 由于这两个信使系统都是由前部的GnRH激活的， 垂体促性腺激素 4.鉴定介导雌二醇阳性的去甲肾上腺素神经元 反馈行动。我们建议：精确地确定哪些 去甲肾上腺素能细胞群投射到GnRH周核和GnRH 正中隆起中的轴突终末; B.以确定这些 去甲肾上腺素能神经元含有类固醇激素受体; c.以确定 性腺类固醇是否会引起mRNA编码的变化， 酪氨酸羟化酶 形态学、生理学和分子生物学的结合 生物学方法将提供关于 GnRH在海马体中的作用，并将揭示一些 GnRH神经系统的调节机制。统称 这些结果对于我们了解大脑是如何 参与调节激素稳态，并可能提供 治疗中枢神经系统不能维持 足够的GnRH释放。

The overall goal of the proposed studies is to characterize further the intracerebral sites of action of gonadotropin releasing hormone (GnRH) and to identify the neurotransmitters which regulate the GnRH neuronal system in the rat. Specifically, we propose to: 1. Identify with immunohistochemistry and "in situ" hybridization the cells in brain which express the GnRH receptor. We recently generated a panel of specific antibodies against synthetic peptide sequences that are part of the intra- and extracellular domains of the pituitary GnRH receptor protein and we have developed cRNA probes to determine the sites of synthesis of the GnRH receptor in the brain. We propose now to determine: a. the location of the GnRH-receptor producing neurons; b. the identity of the neurotransmitters in the GnRH-receptor synthesizing neurons and whether the relative amounts of GnRH-receptor mRNA change in response to estradiol. 2. Identify the GnRH-mediated effects on hippocampal neurons. During the prior funding period we identified and characterized the structure/binding relationships of the brain GnRH receptors and showed that GnRH causes a transient induction of c-fos in certain hippocampal neurons. We propose now to determine whether GnRH causes the release of neuroactive messengers from the hippocampus and whether this effect is modulated by gonadal steroids. 3. Identify the second messenger systems which transmit the GnRH signal to the inside of the hippocampal target neurons. We will focus on the role of Ca++-influx and redistribution as well as on inositol phosphate hydrolysis since both messenger systems are activated by GnRH in the anterior pituitary gonadotropes. 4. Identify the norepinephrine neurons which mediate estradiol positive feedback actions. We propose: a. to determine precisely which noradrenergic cell groups project to the GnRH perikarya and to the GnRH axon terminals in the median eminence; b. to determine if these noradrenergic neurons contain steroid hormone receptors; c. to determine whether the gonadal steroids cause a change in the mRNA encoding for tyrosine hydroxylase. The proposed combination of morphological, physiological and molecular biological approaches will provide detailed information on the nature of the effects of GnRH in the hippocampus and will reveal some of the mechanisms by which the GnRH neuronal system is regulated. Together, the results will be important for our basic understanding of how the brain participates in the regulation of hormonal homeostasis and may provide clues for treatment of disorders caused by a central failure to maintain an adequate GnRH release.