TRANSPORTER REGULATION OF GABAB-MEDIATED TRANSMISSION IN THE THALAMUS

丘脑中 GABAB 介导的传输的转运蛋白调节

基本信息

批准号：
8171756
负责人：
John R Huguenard
金额：
$ 0.11万
依托单位：
CARNEGIE-MELLON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-08-01 至 2013-07-31
项目状态：
已结题

项目摘要

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. Many factors ranging from neurotransmitter release to receptor localization to neurotransmitter uptake mechanisms will affect GABA-mediated synaptic inhibition, especially for metabotropic (GABAB-mediated) responses. As postsynaptic GABAB receptors are localized primarily outside of synaptic sites (ie extrasynaptic), it is hypothesized that GABA transporters (GATs), which function to remove extracellular GABA, limit the extent of GABA spillover and, therefore, GABAB receptor activation. To better understand how GATs regulate GABA spillover, we are examining the roles of two GATs, GAT1 and GAT3, in defining features of GABAB IPSCs in the rat thalamus. Our electrophysiology data demonstrate that GAT1 and GAT3 differentially regulate the amplitude and kinetics of GABAB IPSCs. Our anatomical data suggest that these different GAT1/3 actions result from differences in subcellular localization and density of the two GATs. Specifically, GAT1 expression is primarily perisynaptic, while GAT3 is found in both peri- and more distal extra-synaptic regions. We are beginning to explore how such differential localization can influence GABAB currents. We are currently using computational approaches to explore how GAT localization regulates GABA diffusion in the thalamus, and how such regulation determines the properties of GABAB IPSCs. Specifically, we are using MCell, a modeling platform that tracks the stochastic nature of diffusing molecules in 3-dimensional microphysiological environments using Monte Carlo algorithms (Stiles and Bartol, 2001). Our simpler, less computationally-intensive models indicate that differential GAT1/3 localization provides a mechanism by which GABA transients can be modulated to enable distinct GABAB IPSC amplitude and kinetic changes. We now would like to verify these initial findings in more complex models. Dr. Joel Stiles suggested that we utilize resources offered by the Pittsburg Supercomputing Center to run our new models. Therefore, in following his suggestion, we are applying for these resources to complete our project. We would like user accounts for Mark Beenhakker and John Huguenard

该子项目是利用该技术的众多研究子项目之一资源由 NIH/NCRR 资助的中心拨款提供。子项目和研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金，因此可以在其他 CRISP 条目中表示。列出的机构是对于中心来说，它不一定是研究者的机构。从神经递质释放到受体定位再到神经递质摄取机制的许多因素都会影响 GABA 介导的突触抑制，尤其是代谢型（GABAB 介导的）反应。由于突触后 GABAB 受体主要位于突触位点之外（即突触外），因此推测 GABA 转运蛋白 (GAT) 的作用是去除细胞外 GABA，限制 GABA 溢出的程度，从而限制 GABAB 受体的激活。为了更好地了解 GAT 如何调节 GABA 溢出，我们正在研究两种 GAT（GAT1 和 GAT3）在定义大鼠丘脑 GABAB IPSC 特征中的作用。我们的电生理学数据表明，GAT1 和 GAT3 差异调节 GABAB IPSC 的振幅和动力学。我们的解剖数据表明，这些不同的 GAT1/3 作用是由两种 GAT 的亚细胞定位和密度差异造成的。具体来说，GAT1 表达主要在突触周围，而 GAT3 在突触周围和更远端的突触外区域都有表达。我们开始探索这种差异定位如何影响 GABAB 电流。我们目前正在使用计算方法来探索 GAT 定位如何调节丘脑中的 GABA 扩散，以及这种调节如何决定 GABAB IPSC 的特性。具体来说，我们正在使用 MCell，这是一个建模平台，它使用蒙特卡罗算法跟踪 3 维微生理环境中扩散分子的随机性质（Stiles 和 Bartol，2001）。我们更简单、计算强度较低的模型表明，差异 GAT1/3 定位提供了一种机制，通过该机制可以调节 GABA 瞬态，以实现不同的 GABAB IPSC 幅度和动力学变化。我们现在想在更复杂的模型中验证这些初步发现。 Joel Stiles 博士建议我们利用匹兹堡超级计算中心提供的资源来运行我们的新模型。因此，根据他的建议，我们正在申请这些资源来完成我们的项目。我们想要 Mark Beenhakker 和 John Huguenard 的用户帐户