MODULATION OF GLUTAMATE SYNAPSES IN NEONATAL CORTEX

皮质突触的结构完整性改变已在各种形式的智力迟钝中得到证实，包括那些可归因于染色体异常的智力迟钝（例如，唐氏综合征、脆性X染色体综合征、Angelman综合征、Praeder-Willi综合征、William综合征）、产前暴露于致畸剂（例如，乙醇）和严重的新生儿癫痫发作。大多数这些结构缺陷位于树突棘上的突触处，树突棘是突触能输入的部位，它们可以发生在人类和动物模型中。在正常发育过程中，这些突触的效率、分布和结构受到经验、神经活动和其他神经递质（如5-羟色胺）的显著调节。（干扰正常的神经元能突触传递可导致癫痫发作、神经毒性和异常皮质结构的发展）。这个项目是一个多方面的调查（1）皮层谷氨酸突触的初始分子组装（项目一）;（2）在发展过程中传递行为相关信号的能力（项目二）;和（3）在出生后发育期间通过（i）两种相邻的细胞类型-皮质下白色物质神经元和星形胶质细胞，（ii）调节剂，5-羟色胺（5-HT）和一氧化氮，以及（iii）5-HT和谷氨酸神经递质转运蛋白（项目III、IV和V）。发育神经生物学成像核心（核心B）和行政/项目开发核心（核心A）神经生物学成像核心（核心B）和行政/项目开发核心（核心A）将提供关键服务，并将促进项目之间的协同作用。通过了解这些突触的分子组成，它们在生理环境中的功能特性，以及它们在正常新生儿中通过内在门控通路进行修饰的机制，该项目将为理解发育中的谷氨酸突触对MR中损害突触结构和功能的会聚过程的敏感性提供实质性的新基础。

Altered structural integrity of cortical synapses has been demonstrated in a variety of forms of mental retardation, including those attributable to chromosomal abnormalities (e.g., Down Syndrome, Fragile X, Angelman Syndrome, Praeder-Willi Syndrome, William's Syndrome), prenatal exposure to teratogens (e.g., ethanol) and severe neonatal seizures. Most of these structural defects are at synapses located on dendritic spines, sites of glutamatergic input, and they can occur in humans and animal models. The efficiency, distribution, and structure of these glutamatergic cortical synapses undergo substantial modulation by experience, neural activity, and other neurotransmitters such as serotonin during normal development. (Interference with normal glutamatergic synaptic transmission can lead to seizures, neurotoxicity, and development of abnormal cortical architecture). This program project is a multi-faceted inquiry into (1) the initial molecular assembly of the cortical glutamate synapse (Project I); (2) its capacity for transferring behaviorally relevant signals during development (Project II); and (3) its modulating during postnatal development by (i) two neighboring cell types-subcortical white matter neurons and astrocytes, (ii) the modulators, serotonin (5-HT) and nitric oxide, and (iii) the 5-HT and glutamate neurotransmitter transporters (Projects III, IV, and V). A Developmental Neurobiology Imaging Core (Core B) and an Administration/Project Development Core (Core A) Neurobiology Imaging Core (Core B) and an Administration/Project Development Core (Core A) will provide critical services and will promote synergy among projects. By learning the molecular components of these synapses, their functional properties in a physiological context, and the mechanisms of their modification by intrinsic gating pathway in the normal neonate, this project will provide a substantial new basis for understanding the sensitivity of developing glutamate synapses to the convergent processes that compromise synaptic structure and function in MR.