CELLULAR PHYSIOLOGY OF CORTICAL DEVELOPMENT

描述：拟议的研究涉及以下基本机制： 中枢神经系统中选择性突触的形成 发展。他们专注于单个已识别突触的形成 在大鼠海马区，从苔藓纤维到 CA3锥体细胞。两个互补的实验系统来自 新生大鼠将使用：(1)海马片，和(2)齿状- 海马细胞共培养。这些实验将使用共焦 细胞结构改变的时间推移分析，功能成像 测量和电生理学，辅以回顾 细胞学，以识别和表征新生突触。三大 将继续提出以下问题： 1.未来突触伙伴的动作--一个苔藓 纤维和一个树突--产生最初的突触 联系？树突状丝状基座在 突触发生？传入轴突是否导致丝状足突的伸展？ 突触接触必须发生在特定的区域，如前导联 生长锥体或轴突或树突的顶端？多么 轴突生长和突触形成事件是精心策划的，以形成 周期性传递性突触静脉曲张？ 2.最初的接触点是如何成熟为最终的突触的？ 一种新的成像突触小泡回收的荧光方法， 电生理学、钙成像和回顾性免疫组织化学 将使用电子显微镜来分析变化的顺序 在分子结构和功能状态中 最初的接触和完全分化的突触。 3.初始接触或成熟过程是否受 电活动？在发展的基线分析之后 在前面段落中定义的过程中，实验将 以检测其中每一个的电活动的影响 流程。 通过提供关于细胞和 中枢神经系统突触形成的分子机制，这些研究可能提供 对神经出生等发育障碍的新见解 缺陷、学习缺陷和智力低下，并建议 对抗中风、中枢神经系统创伤所致神经缺陷的治疗方法 以及退化性疾病，如帕金森氏症和阿尔茨海默氏症。 此外，由于苔藓纤维发芽异常与 几种癫痫发作障碍，拟议的研究可能会产生结果 立即适用于癫痫。

DESCRIPTION: The proposed studies address basic mechanisms of selective synapse formation during central nervous system (CNS) development. They focus on the formation of a single identified synapse in the rat hippocampus, the en passant synapse from mossy fiber to CA3 pyramidal cell. Two complementary experimental systems from neonatal rat will be used: (1) a hippocampal slice, and (2) dentate- hippocampal cell co-cultures. The experiments will employ confocal time-lapse analysis of cytoarchitectural changes, functional imaging measurements and electrophysiology, supplemented by retrospective cytologies to identify and characterize nascent synapses. Three major questions will be pursued: 1. What motions of the prospective synaptic partners -- one mossy fiber and one dendrite -- bring about the initial synaptogenic contact? What is the role of the dendritic filopodium in synaptogenesis? Do afferent axons induce the extension of filopodia? Must synaptogenic contacts occur at specialized regions such as leading growth cones or the tips of axonal or dendritic filopodia? How are axon growth and synapse formation events orchestrated to form the periodic en passant synaptic varicosities? 2. How does the initial contact site mature into a definitive synapse? A new fluorescence method for imaging synaptic vesicle recycling, electrophysiology, Ca imaging and retrospective immunohistochemistry and electron microscopy will be used to analyze the sequence of changes in molecular architecture and functional status that intervene between the initial contact and the fully differentiated synapse. 3. Are initial contact or maturation processes influenced by electrical activity? After baseline analyses of the developmental processes defined in the preceding paragraphs, experiments will be carried out to detect effects of electrical activity of each of those processes. By providing new information about the basis of cellular and molecular mechanisms of CNS synapse formation, these studies may offer new insights into developmental disorders such as neurological birth defects, learning deficits, and mental retardation, and suggest therapies to combat the neural deficits produced by stroke, CNS trauma and degenerative diseases such as Parkinson's and Alzheimer's. In addition, since abnormal mossy fiber sprouting is implicated in several seizure disorders, the proposed research could produce results immediately applicable to epilepsy.