AMPA RECEPTOR ACTIVITY AND DENDRITE MORPHOGENESIS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 虽然NMDA受体参与出生后活动依赖性可塑性是公认的，但对非NMDA受体在这一过程中的功能了解较少。 在运动神经元中，AMPA GluR 1亚基在发育过程中表达，但当神经元达到其成熟表型时下调。 以前的实验表明，在运动神经元的过度表达GluR 1在其发展的结果在树突分支点的数量增加，这表明树突可塑性的某些方面控制AMPA受体在这些神经元的表达。 该提案将使用实时成像的哺乳动物脊髓培养物和皮质培养物转染个别AMPA受体亚单位，以测量树突重组的动态速率。 将使用双顺反子载体转染研究构成钙渗透性和钙不渗透性AMPA受体的亚基的精确发育作用。 定量PCR将用于建立AMPA受体在发育神经元中表达的时间模式。 此外，暂时限制敲低个别AMPA受体使用RNAi将调查是否AMPA受体的发育调控限制树突的形态可塑性。 实验将研究神经元活动本身是否调节特定AMPA受体亚单位的表达。 在培养的神经元的研究将补充从体内模型，采用有针对性的敲除AMPA受体亚基和它们的细胞内信号分子，从运动和姿势功能障碍模型的观察。 确定AMPA受体如何支配树突可塑性的特定特征是理解神经元发育过程中功能连接如何调节的基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. While the involvement of NMDA receptors in postnatal activity-dependent plasticity is well established, less is understood about the function of non-NMDA receptors in this process. In motor neurons, the AMPA GluR1 subunit is expressed during development, but is downregulated when neurons have attained their mature phenotype. Previous experiments have shown that overexpression of GluR1 in motor neurons at the end of their development results in an increased number of dendrite branch-points, suggesting that some aspects of dendrite plasticity are controlled by AMPA receptor expression in these neurons. This proposal will use real-time imaging of mammalian spinal cord cultures and cortical cultures transfected with individual AMPA receptor subunits, to measure dynamic rates of dendrite reorganization. The precise developmental role of subunits which constitute calcium-permeable and calcium-impermeable AMPA receptors will be investigated using transfection of bicistronic vectors. Quantitative PCR will be used to establish the temporal pattern of AMPA receptor expression in developing neurons. Further, temporally restricted knock-down of individual AMPA receptors using RNAi will investigate whether developmental regulation of AMPA receptors limits morphological plasticity of dendrites. Experiments will investigate whether neuronal activity itself regulates expression of specific AMPA receptor subunits. Studies in cultured neurons will be complemented with observations drawn from in vivo models which employ targeted knockout of AMPA receptor subunits and their intracellular signaling molecules, and from models of locomotor and postural dysfunction. Determining how AMPA receptors govern specific features of dendritic plasticity is fundamental in comprehending how functional connectivity may be modulated during neuronal development.