IDENTIFYING AND CHARACTERIZING BRAIN GNRH RECEPTORS

拟议研究的总体目标是进一步描述 促性腺激素释放激素(GnRH)的脑内作用部位和 确定调节促性腺激素释放激素神经系统的神经递质 在老鼠身上。具体来说，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部分胞内区和胞外区 受体蛋白，我们已经开发了cna探针来确定位点 大脑中促性腺激素释放激素受体的合成。我们现在提议 确定：A.产生GnRH受体的神经元的位置；B. 促性腺激素释放激素受体合成中神经递质的识别 神经元和GnRH受体mRNA的相对量是否发生变化 对雌二醇的反应。 2.明确促性腺激素释放激素对海马神经元的影响。在.期间 之前的资助期，我们确定并描述了结构/结合 脑GnRH受体的关系，并表明GnRH导致 C-fos在某些海马神经元中的瞬时诱导。我们建议 现在要确定促性腺激素释放激素是否导致神经活性信使的释放 以及这种作用是否受性腺的调节 类固醇。 3.识别将GnRH信号传递到 海马靶神经元的内部。我们将重点关注 钙离子内流和再分配及其对肌醇磷酸水解酶的影响 由于这两个信使系统都是由GnRH在前部激活的 垂体促性腺激素。 4.鉴定参与雌激素阳性反应的去甲肾上腺素神经元 反馈操作。我们建议：a.准确地确定 去甲肾上腺素能细胞群投射到GnRH包膜和GnRH 正中隆起的轴突终末；B.确定这些 去甲肾上腺素能神经元含有类固醇激素受体；C.确定 性腺类固醇是否会引起编码基因的改变 酪氨酸羟基酶。 提出了形态、生理和分子的结合 生物学方法将提供有关生物的性质的详细信息 GnRH在海马区的作用，并将揭示一些 GnRH神经系统的调节机制。团结在一起， 研究结果对于我们基本理解大脑是如何 参与调节荷尔蒙动态平衡，并可能提供 中枢失控引起的疾病的治疗线索 足够的促性腺激素释放激素。

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.