NEUROENDOCRINE BASES OF REPRODUCTIVE BEHAVIOR

生殖行为的神经内分泌基础

基本信息

批准号：
6343158
负责人：
ANNE M ETGEN
金额：
$ 30.32万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
1993
资助国家：
美国
起止时间：
1993-01-01 至 2001-12-31
项目状态：
已结题

项目摘要

(Adapted from the investigator's abstract): The ovarian hormones estradiol (E) and progesterone (P) act in the hypothalamus and preoptic area (HPOA) to stimulate the preovulatory release of pituitary gonadotropins and coordinate the expression of reproductive mating behavior, namely lordosis by the female through the action of norepinephrine (NE). The goal of the proposed research is to examine the molecular mechanisms by which estradiol and progesterone modulate signal transduction on alpha1-and beta-adrenoceptors in the HPOA and to relate these to the expression of reproductive behavior. Specific Aim 1 will test the hypothesis that estradiol elevates alpha1B-adrenoceptors in populations of HPOA neurons that express ER. Immunocytochemical approaches will be employed to determine: 1) whether E increases alpha1B-adrenoceptor protein in regions of the HPOA that also express ER; 2) whether A1B - adrenoceptors and ER are colocalized in some or all of these neurons; and 3) whether hypothalamic neurons expressing alpha1B-adrenoceptors project to the midbrain central gray (MCG). Specific aim 2 will test the hypothesis that in the HPOA of E-primed females P will switch alpha1 adrenoceptor signaling from activation of phospholipase C to calcium- dependent activation of the nitric oxide (NO)/soluble guanylyl cyclase pathway. Support for this hypothesis is derived from the observation that alpha1-adrenergic activation of NO synthesis influences the preovulatory release of LH and because expression of reproductive behavior in E+P treated female rats is inhibited by NO synthetase inhibitors and inhibitors of soluble guanylyl cyclase. Specific aim 3 will test the hypothesis that E increases the expression of one or more protein kinase C (PKC) isoenzymes in the HPOA. PKC is a major downstream mediator of alpha1-adrenergic signal transduction; hence, induction of PKC could further amplify alpha1-adrenergic signaling in the HPOA. Experiments will utilize assays of PKC catalytic activity as well as phorbol ester binding and Western Blots to identify the separate isoenzymes. Specific Aim 4 will test the hypothesis that E regulates molecules involved in adrenergic receptor-G protein coupling. Molecular biological and immunological methods will be used to determine the effects of E on: 1) mRNA and protein levels of b-adrenergic receptor kinase 1 and 2 (b-ARK1, and b-ARK2) and 2) the mRNA and protein levels of b-arrestin1 and b-arrestin2. These are significant questions because b-ARKs and b-arrestins impede the interactions of b-adrenergic, a2-adrenergic and u-opioid receptors with G proteins, and they find that E treatment decreases the function of all three of these receptors in the HPOA with measurably downregulating the receptors.

（改编自研究者的摘要）：卵巢激素雌二醇 (E) 和孕酮 (P) 作用于下丘脑和视前区区域（HPOA）刺激垂体的排卵前释放促性腺激素并协调生殖交配的表达行为，即女性通过以下动作造成的脊柱前凸去甲肾上腺素（NE）。拟议研究的目标是检查雌二醇和孕酮调节信号的分子机制 HPOA 中 α1 和 β 肾上腺素受体的转导及其相关性这些都是生殖行为的表达。具体目标1将测试雌二醇可提高 α1B 肾上腺素受体的假设表达 ER 的 HPOA 神经元群体。免疫细胞化学方法将用于确定：1) E是否增加α1B-肾上腺素受体 HPOA 区域中也表达 ER 的蛋白质； 2) 是否A1B- 肾上腺素受体和 ER 共定位于部分或全部神经元中；和 3) 下丘脑神经元是否表达α1B-肾上腺素受体到中脑中央灰（MCG）。具体目标 2 将测试假设在 E 启动雌性的 HPOA 中 P 将转换 alpha1 肾上腺素受体信号传导从磷脂酶 C 的激活到钙- 一氧化氮 (NO)/可溶性鸟苷酸环化酶的依赖性激活途径。对这一假设的支持来自以下观察： α1-肾上腺素能激活 NO 合成影响排卵前 LH 的释放以及 E+P 中生殖行为的表达接受治疗的雌性大鼠受到 NO 合成酶抑制剂的抑制，并且可溶性鸟苷酸环化酶抑制剂。具体目标 3 将测试 E 增加一种或多种蛋白激酶表达的假设 HPOA 中的 C (PKC) 同工酶。 PKC 是下游的主要调节者 α1-肾上腺素能信号转导；因此，PKC 的诱导可以进一步放大 HPOA 中的 α1-肾上腺素信号传导。实验将利用 PKC 催化活性以及佛波酯结合分析和蛋白质印迹来鉴定单独的同工酶。具体目标 4 将检验 E 调节参与肾上腺素能的分子的假设受体-G蛋白偶联。分子生物学和免疫学方法将用于确定 E 对以下方面的影响：1) mRNA 和蛋白质 b-肾上腺素受体激酶 1 和 2（b-ARK1 和 b-ARK2）和 2）的水平 b-arrestin1 和 b-arrestin2 的 mRNA 和蛋白质水平。这些都是重要的问题，因为 b-ARK 和 b-arrestins 阻碍了 b-肾上腺素能、a2-肾上腺素能和 u-阿片受体与 G 的相互作用蛋白质，他们发现 E 治疗会降低所有蛋白质的功能 HPOA 中的三个受体可显着下调受体。