MOLECULAR CORRELATES OF ADULT SYNAPTOGENESIS

成人突触发生的分子相关性

• 批准号: 6392615
• 负责人: WILLIAM B LEVY
• 金额: $ 22.7万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6392615
• 关键词: developmental neurobiology; estradiol; estrus; female; gender difference; gene expression; genetic mapping; hippocampus; hormone regulation /control mechanism; in situ hybridization; laboratory rat; neurogenetics; ovariectomy; polymerase chain reaction; protein localization; synaptogenesis; voltage /patch clamp

DESCRIPTION (Verbatim from the Applicant's Abstract): The hippocampus is an important cognitive brain region by virtue of its critical role in learning and memory. In the adult hippocampus of the female rat, the CA3-CA1 synapses undergo phasic cycles of syanptogenesis and synapse shedding with each 4 or 5 day estrous cycle. Although this cycle requires the ovarian steroid estrogen, the excitatory pyramidal neurons in CA1 and CA3 lack the conventional, genomic estrogen receptor (ER alpha). This remarkable observation leads to many, unanswered questions about the control of ovarian steroid-dependent cycle of adult synaptogenesis in the hippocampus. It also begs us to ask whether this same cycle also occurs in cerebral cortex. Using the molecular biological techniques of PCR, Northern and Southern blots, and differential display, we will uncover a set of molecules that are selectively synthesized in an estradiol-dependent manner in hippocampal CA1 and CA3. The time course of selective synthesis will enable us to define a temporal cascade of expressed sequences from early time points, those presumably controlling transcription factors, through later ones, possibly including sequences involved in synapse assembly. By pharmacologically blocking estradiol-dependent synapse formation with an NMDA receptor antagonist, and independently, by hormonally undoing synapses already formed, we will identify a particularly interesting subset of these expressed transcripts. This selective subset will include estradiol-dependent transcripts specific to the synaptogenetic cascade. Interpreting the roles played by the estradiol-dependent transcripts will be facilitated by electrophysiological correlations, anatomical localization, and by structural similarities to known molecules. Using naturally cycling females and ovariectomized animals receiving estradiol replacement, we will electrophysiologically assess NMDA receptor function in CA1 and correlate this with altered gene expression. In situ hybridization, supplemented as necessary with microdissection, will permit the cellular localization of these novel gene products to pyramidal and/or nonpyramidal neurons and/or glia. In situ hybridization will subsequently be used 1) to search for similar expression patterns in cerebral cortex and hypothalamus, and 2) to compare this form of adult synaptogenesis with that in the developmentally immature, male rat. Finally, we begin a series of experiments, including cloning and mapping the newly discovered genes to mouse and human chromosomes. These studies will eventually culminate in testing the function of these novel gene products in the genetically altered mouse.

描述（逐字研究申请人的摘要）：海马是一个 重要的认知大脑区域在学习中的关键作用和 记忆。在雌性大鼠的成年海马中，CA3-CA1突触 每4或5都会经历Syanptogenesofen和Synapse脱落的阶段循环 日间发情周期。尽管此周期需要卵巢类固醇雌激素，但 CA1和CA3中的兴奋性锥体神经元缺乏常规的基因组 雌激素受体（ERα）。这种非凡的观察导致许多人 关于控制卵巢类固醇依赖性周期的未解决的问题 海马中的成年突触发生。它也恳求我们问是否 同一周期也发生在大脑皮层中。 使用PCR，北部和南部印迹的分子生物学技术， 和差分显示，我们将发现一组分子 以海马CA1和 CA3。选择性合成的时间过程将使我们能够定义一个时间 从早期点出发的级数级联，大概是这些序列 通过以后的转录因子控制转录因子，可能包括 突触组件涉及的序列。通过药理阻塞 雌二醇依赖性突触与NMDA受体拮抗剂，并 独立地，通过已经形成的荷尔蒙释放突触，我们将确定 这些表达的转录本的一个特别有趣的子集。这 选择性子集将包括特定于雌二醇的转录本 突触发生级联。 解释与雌二醇相关的成绩单扮演的角色将是 由电生理相关性，解剖学定位和 通过与已知分子的结构相似性。使用自然骑自行车的女性 和卵巢切除的动物接受雌二醇替代，我们将 电生理评估CA1中的NMDA受体功能并将其关联 基因表达改变。原位杂交，必要的补充 通过微分解，将允许这些新基因的细胞定位 产生锥体和/或非锥虫神经元和/或神经胶质的产品。原位 杂交将随后使用1）搜索相似的表达 大脑皮层和下丘脑的模式，以及2）比较这种形式 成人突触发生，在发育中不成熟的男性大鼠中。 最后，我们开始了一系列实验，包括克隆和映射 新发现的小鼠和人类染色体基因。这些研究会 最终最终在测试这些新基因产物的功能中最终 遗传改变的小鼠。