DIFFUSION OF SUBSTANCES THROUGH THE BRAIN

描述(调查人员摘要)：总体目标是 描述物质是如何在细胞外空间扩散的 大脑。这将澄清细胞外空间的结构， 展示细胞外化学交流的潜力。这个 这项研究将有助于改善治疗干预和辅助靶向 脑组织中的药物和生物活性物质。适当的解决方案 扩散方程将被用来解释实验 结果。所有的实验都将在不同脑组织的切片上进行 Spraogue-Dawley大鼠的区域。三个具体目标是：1) 改进测量扩散的光学方法2)量化扩散 和多巴胺的摄取描述了大脑发育过程中的扩散。 具体目标1是进一步发展定量光学成像和 分析扩散的相关理论。新的实验和理论 这些方法将使用标记有 荧光染料。这项技术将扩展到荧光右旋糖苷 分子量和蛋白质均在70 kDa以上。它将测量 细胞外体积分数和细胞表观曲度 胞外空间和账户的同质和异质区域 对于扩散物质到细胞内隔室的损失和 在切片的表面。这些方法将具有广泛的适用性。 除了这项提议之外。 具体目标2是研究Michaelis-Menten的相关作用 多巴胺在胞外迁移的动力学和扩散 太空。快速扫描循环伏安法及其数值解 扩散方程将描述多巴胺的释放行为 压力从微吸管射入新纹状体，即核 伏隔核和黑质。这项工作将有助于决定 多巴胺作为突触外体积传递介质的潜力 并将为多巴胺替代的建模提供数据 改善帕金森氏症的策略。 具体目标3是表征化合物的扩散特性 正常发育的大脑和缺氧状态下的细胞外空间， 缺血和渗透应激。荧光右旋糖苷和蛋白质将是 与定量光学成像一起使用来确定变化如何 细胞外间隙的结构影响脑组织切片的扩散。 新皮质，从出生后第1天到第21天，在成年大脑中。 切片也将在有和没有葡萄糖的情况下受到缺氧(TO 模拟缺血)和低渗和高渗应激，看看 发育中的大脑结构会对这些侮辱做出反应。蒙特卡洛 模拟将被编程为对无法由描述的数据建模 扩散方程的解析或数值解。这些 实验将有助于讨论扩散在气候变化中的作用 发展过程和结构的易感性 细胞外空间在不同年龄段受到各种侮辱。

DESCRIPTION (Investigator's Abstract): The overall goal is to characterize how substances diffuse in the extracellular space of the brain. This will clarify the structure of extracellular space, demonstrate the potential for extracellular chemical communication. The study will help improve therapeutic intervention and aid targeting of drugs and bioactive substances in brain tissue. Appropriate solutions to the diffusion equation will be used to interpret experimental results. All experiments will be made on slices from various brain regions of Sprague-Dawley rats. The three Specific Aims are to: 1) improve optical methods for measuring diffusion 2) quantify the diffusion and uptake of dopamine 3) describe diffusion in the developing brain. Specific Aim 1 is further development of quantitative optical imaging and related theory for analyzing diffusion. New experimental and theoretical methods will use high-resolution imaging of molecules tagged with fluorescent dyes. The technique will be extended to fluorescent dextrans above 70 kDa in molecular weight and proteins. It will measure extracellular volume fraction as well as apparent tortuosity in homogeneous and heterogeneous regions of extracellular space and account for loss of the diffusing substance to the intracellular compartment and at the surfaces of slices. These methods will have wide applicability beyond this proposal. Specific Aim 2 is to study the relative roles of Michaelis-Menten kinetics and diffusion in the migration of dopamine in the extracellular space. Fast-scan cyclic voltametry and numerical solutions to the diffusion equation will describe the behavior of dopamine release by pressure ejection from a micropipette into the neostriatum, the nucleus accumbens and the substantia nigra. This work will help to decide the potential of dopamine as an agent for extra-synaptic volume transmission and will provide data for the modeling of dopamine replacement strategies to ameliorate Parkinson's Disease. Specific Aim 3 is to characterize the diffusion properties of the extracellular space in the normal developing brain and under hypoxia, ischemic and osmotic stress. Fluorescent dextrans and proteins will be used with quantitative optical imaging to determine how the changing structures of the extracellular space affect diffusion in slices of the neocortex, from post- natal day 1 to day 21 and in the adult brain. Slices will also be subjected to hypoxia with and without glucose (to simulate ischemia) and to hypo- and hyperosmotic stress to see how the developing brain structure reacts to these insults. A Monte Carlo simulation will be programmed to model data that cannot be described by analytical or numerical solutions to the diffusion equation. These experiments will aid discussions of the role of diffusion in the developmental process and how susceptible is the structure of extracellular space to various insults at different ages.