DEVELOPMENTAL REGULATION OF GLUTAMATE RECEPTOR FUNCTION

描述：申请人正在使用上级的表层 丘（sSC）在啮齿类动物研究神经之间的关系 活动和减少NMDA受体（NR）电流持续时间， 发生在发展过程中。 申请人已经表明，突触NR电流 在大鼠sSC中，衰减时间突然减少（24小时），与 NR亚基NR 1和NR 2A的转录物和蛋白质的变化。 这 在睁眼前和视网膜丘图结束时， 精致。 我们还表明，GABA能抑制， 调节NR功能异突触，开始较晚，后睁开眼睛， 在皮质丘地图细化过程中。 然而，长期应用 从P8开始，sSC的NMDA异常增加GABA能抑制 早期和破坏NR调节的正常模式。 这项建议会 测试从这项工作中出现的四个假设：（1）突触下 NR的翻译后蛋白修饰或突触下调节 亚基掺入负责NR电流 衰减时间减少，（2）NR 2A亚基水平的增加也 促成这种变化，（3）NR激活触发NR电流 衰变带减少和/或NR亚基组成改变，以及（4） 增强的GABA能抑制是对NR激活的特异性反应 在一个有限的发展关键时期。 为了测定NMDA处理的大鼠sSC中的转录物和蛋白质变化， 建议将使用RNase保护测定，竞争性PCR，免疫印迹， 免疫细胞化学、免疫沉淀和细胞分级分离程序。 切片和分离的sSC培养物中的全细胞膜片钳，沿着 与培养物中的钙成像，将用于测定NR功能。 在 此外，将检查野生型和NR 2A敲除小鼠的sSC， 确定该亚基是否有助于NR电流的快速变化， 敲除的GABA系统是否由于 预期由该突变引起的活性增加。 申请人寻求对以下相互作用的机械理解： 神经传递相关的基因产物和活动在发展 神经回路 这些发现应该有助于治愈或治疗 被认为与环境或表观遗传有关的儿童期疾病 成分 这些症状包括轻度言语和语言缺陷， 毁灭性和普遍的神经系统疾病，如癫痫、脑血管疾病 麻痹和自闭症

DESCRIPTION: The applicant is using the superficial layers of the superior colliculus (sSC) in rodents to study the relationship between neural activity and the reduction of NMDA receptor (NR) current duration that occurs during development. The applicant has shown that synaptic NR current decay time decreases abruptly (24hrs) in the rat sSC in association with changes in both transcripts and protein for NR subunits NR1 and NR2A. This decrease occurs before eye opening and at the end of retinocollicular map refinement. We have also shown that GABAergic inhibition, which can modulate NR function heterosynaptically, begins later, after eye-opening and during cortico-collicular map refinement. However, chronic application of NMDA to the sSC beginning at P8 increases GABAergic inhibition abnormally early and disrupts the normal pattern of NR regulation. This proposal will test four hypotheses that emerge from this work: (1) that subsynaptic post-translational protein modification or subsynaptic regulation of NR subunit incorporation is responsible for the speed with which NR current decay time decreases, (2) that the increase in NR2A subunit level also contributes to this change, (3) that NR activation triggers the NR current decay tie decrease and/or NR subunit composition changes and (4) that increased GABAergic inhibition is a specific response to NR activation during a restricted developmental critical period. To assay transcript and protein changes in NMDA-treated rat sSC, the proposal will use RNase protection assays, competitive PCR, immunoblotting, immunocytochemistry, immunoprecipitation and cell fractionation procedures. Whole-cell patch clamping in slices and in a dissociated sSC culture, along with calcium imaging in culture, will be used to assay NR function. In addition, the sSC of wildtype and NR2A knockout mice will be examined to determine if this subunit contributes to rapid NR current changes and whether the GABA system of the knockout has up-regulated as a result of increases in activity that a re expected to result from this mutation. The applicant seeks a mechanistic understanding of the interaction of neurotransmission-related gene products and activity in the development of neural circuits. The findings should facilitate cures or treatments for disorders of childhood thought to have an environmental or epigenetic component. These range from mild speech and language deficits to devastating and prevalent neurological diseases such as epilepsy, cerebral palsy and autism.