HYPOTHALAMIC NEUROPEPTIDE Y AND REPRODUCTIVE AGING

长期的目标是了解神经内分泌的基础 老年大鼠的无排卵，尤其是在手术中 调节排卵前黄体生成素峰的下丘脑肽能环路。 在雌性大鼠中，规律的周期性是通过精确的计时来维持的 适时、顺序性促性腺激素释放激素和促黄体生成素的排卵前高峰 抑制性(EOP等)和兴奋性(NPY等)的展开 下丘脑的后遗症。由于神经肽Y(NPY)的释放是 在幼年大鼠体内诱导LHRH和LH激增是必须的，我们 假设进行性的、与年龄相关的NPY信号缺陷 产出和/或NPY系统与 神经钟-阿片连接上游，LHRH-LH轴下游， 结果衰老大鼠LHRH-L H峰消失。测试我们的 假设，三个年龄组(青年、中年和老年)的大鼠将 研究的具体目的如下：1)检测神经肽Y神经分泌 在生殖衰老过程中会发生改变，尤其是与 排卵前黄体生成素高峰消失，2)评估中断的原因 (神经分泌)在NPY系统中通过检测NPY系统是否在老年 大鼠保留或丧失对外周正常反应的能力 信号(类固醇)和冲击它的神经系统(阿片类药物) 3)测试连接后兴奋性递进移位 NPY的作用(NPY和NE相互作用对LHRH和LH释放的影响) 导致老年大鼠黄体生成素峰值的丧失。神经肽Y神经分泌会 通过评估信号输出进行评估(体内和体外释放) 以及可用于释放的信号量(肽含量)和 合成(PreproNPY MRNA)。NPY的体内释放将通过以下方法进行测量 从下丘脑中层基底(MBH)推拉插管灌流 垂体前叶(PIT)和体外培养的下丘脑(正中隆起)。 弓状核)孵化。脑内核团的多肽含量与神经肽原原 MBH中的mRNA将在每天的基础上进行研究。神经肽(NPY， 用放射免疫法测定促黄体生成素(LHRH)、促黄体生成素(LH)和类固醇(E_2)。神经肽Y的相互作用 和NE对黄体生成素释放的影响将在体内进行研究，以及NPY和NE的相互作用 Ne on LHRH将通过PPC方法在体内和体外进行释放研究 利用ME-ARC孵化。Pre-proNPY m RNA将用溶液测定 杂交/核酸酶保护试验。 从这些研究中获得的新信息不仅将进一步推动我们的 对生殖衰老的神经内分泌基础的了解，但 也将作为未来阐明细胞和 离散信号(NPY)作用的分子机制 离散神经解剖定位(视前内侧区/正中 隆起/凹陷)对幼鼠的特定功能(排卵性黄体生成素高峰)。

The long-term objectives are to understand the neuroendocrine basis of anovulation in aging rats especially with regard to operation of hypothalamic peptidergic circuits that regulate the preovulatory LH surge. In the female rat, regular cyclicity is maintained by a precise timing in the preovulatory surges of LHRH and LH evoked by the timely, sequential unfolding of inhibitory (EOP and other) and excitatory (NPY and other) sequelae within the hypothalamus. Since neuropeptide Y (NPY) release is obligatory in the induction of LHRH and LH surges in young rats, we hypothesize that a progressive, age-related deficit in either NPY signal output and/or a derangement in the relationship of the NPY system with the neural clock-opioid link upstream, and the LHRH-LH axis downstream, results in disappearance of LHRH-LH surges in senescent rats. To test our hypothesis, rats of three age groups (young, middle-aged and old) will be studied with the following specific aims: 1) test that NPY neurosecretion is altered during reproductive senescence, especially in association with a loss of the preovulatory LH surge, 2) evaluate the cause of disruption (neurosecretion) in the NPY system by examining whether NPY system in old rats retains or loses the capacity to respond normally to peripheral signals (steroids) and to neuronal systems that impinge upon it (opioids) and 3) test that a progressive shift in the post-junctional excitatory action of NPY (interactions between NPY and NE on LHRH and LH release) contributes to the loss of LH surges in aged rats. NPY neurosecretion will be evaluated by assessing the signal output (in vivo and in vitro release) and the amount of signal available for release (peptide content) and synthesis (preproNPY mRNA). In vivo release of NPY will be measured by push-pull cannula perfusion from the media basal hypothalamus (MBH) and anterior pituitary (PIT) and in vitro by hypothalamic (median eminence- arcuate nucleus) incubation. Peptide content in brain nuclei and preproNPY mRNA in the MBH will be studied on a diurnal basis. Neuropeptides (NPY, LHRH), LH and steroid (E2) will be measured by RIA. Interactions of NPY and NE on LH release will be studied in vivo and interactions of NPY and NE on LHRH release will be studied in vivo by the PPC method and in vitro using ME-ARC incubations. PreproNPY mRNA will be measured by solution hybridization/ nuclease protection assay. New information derived from these studies will not only further our understanding on the neuroendocrine basis of reproductive senescence, but will also serve as a framework for future elucidation of cellular and molecular mechanisms involved in the action of a discrete signal (NPY), at discrete neuroanatomical location (medial preoptic area/median eminence/PIT) for a specific function (ovulatory LH surge) in young rats.