MOLECULAR CORRELATES OF ADULT SYNAPTOGENESIS

描述(摘自申请者的摘要)：海马体是一种 重要的认知脑区域，凭借其在学习和学习中的关键作用 记忆。在成年雌性大鼠的海马区，CA3-CA1突触 经历每4到5个突触发生和突触脱落的阶段周期 日发情周期。虽然这个周期需要卵巢类固醇雌激素， CA1和CA3的兴奋性锥体神经元缺乏常规的基因组 雌激素受体(ERα)。这一非凡的观察结果导致了许多人， 卵巢激素依赖周期的控制未解之谜 成体在海马区的突触发生。它还恳请我们问一问，这是否 同样的循环也发生在大脑皮层。 利用PCR、Northern和Southern杂交等分子生物学技术， 和差异显示，我们将发现一组分子 在海马CA1区以雌激素依赖的方式选择性合成 CA3.选择性合成的时间进程将使我们能够定义时间 来自早期时间点的表达序列的级联，假设 控制转录因子，通过后来的转录因子，可能包括 参与突触组装的序列。通过药物阻断 雌激素依赖的突触与NMDA受体拮抗剂的形成，以及 独立地，通过荷尔蒙破坏已经形成的突触，我们将识别 这些表达的转录本中有一个特别有趣的子集。这 选择性的子集将包括雌激素依赖的转录本 突触发生级联反应。 解释依赖雌激素的转录本所起的作用将是 由电生理关联、解剖定位和 通过与已知分子的结构相似。使用自然骑自行车的雌性 和接受雌激素替代的卵巢切除动物，我们将 电生理学评估CA1区NMDA受体功能及其相互关系 基因表达发生了改变。原位杂交，必要时补充 通过显微切割，将允许这些新基因的细胞定位 产物通向锥体和/或非锥体神经元和/或胶质细胞。就地 随后将使用杂交来搜索相似的表达 大脑皮层和下丘脑的模式，以及2)比较这种形式的 成年大鼠与发育不成熟雄性大鼠的突触发生。 最后，我们开始一系列实验，包括克隆和绘制 新发现的小鼠和人类染色体上的基因。这些研究将 最终在测试这些新基因产物的功能方面达到顶峰 基因改变的小鼠。

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.