Structural and Functional Dysconnectivity in Dopamine/Acetylcholine Circuitry in Repetitive Mild TBI

重复性轻度 TBI 中多巴胺/乙酰胆碱回路的结构和功能脱节

• 批准号: 9916055
• 负责人: C EDWARD DIXON
• 金额: $ 43.04万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9916055
• 关键词: Acetylcholine; Affect; Behavioral; Brain Injuries; Cell Nucleus; Chronic; Diagonal Band of Broca; Diffusion Magnetic Resonance Imaging; Dopamine; Electric Stimulation; Fiber; Fluorescence; Goals; Grant; Hippocampus (Brain); Human; Image; Immunohistochemistry; Impaired cognition; Liquid substance; Measures; Medial; Methods; Microdialysis; Neurologic Deficit; Neurons; Neurotransmitters; Pathway Analysis; Pathway interactions; Percussion; Physical Function; Process; Rattus; Septal Area; Severities; Sorting - Cell Movement; Specificity; Structure; Substantia nigra structure; Synaptosomes; System; Transgenic Organisms; Traumatic Brain Injury; Tyrosine 3-Monooxygenase; Ventral Tegmental Area; basal forebrain; cholinergic; cholinergic neuron; cognitive function; cognitive recovery; emotional functioning; enhanced green fluorescent protein; median forebrain bundle; mild traumatic brain injury; nerve supply; neurotransmission; neurotransmitter release; nigrostriatal pathway; novel; tool; tractography; white matter

Traumatic brain injury (TBI) of all severities can result in chronic disturbances of cognitive, behavioral, emotional, and physical functioning. Recovery of cognitive function after TBI is a dynamic process in which alterations in neurotransmitter systems do not likely occur in isolation. Numerous studies have demonstrated that the dopaminergic (DA) innervation of medial septum and diagonal band of broca (medial septal area [MSA]) regions that are dense with cholinergic neurons can affect hippocampal acetylcholine (ACh) release. The goal of this R21 grant is to evaluate mild repetitive TBI-induced changes in the integrity of dopaminergic/cholinergic connectivity using contemporary tools including diffusion MRI tractography with network analysis, transgenic human tyrosine hydroxylase GFP expressing rats, and Fluorescence activated synaptosomal sorting (FASS) analysis. The overall hypothesis is that TBI produces a loss of DA fiber connectivity, including DAergic innervation of the MSA, which contributes to cholinergic deficits. Aim 1 will determine the effects of repeated mild fluid percussion TBI (rmTBI) on the connectivity of the nigrostriatal pathway using high-definition fiber tracking in conjunction with network topology analysis. Complimentary immunohistochemistry in hTH-GFP rats will be compared to the imaging tractography to enhance specificity to DA circuits. Aim 2 will determine if rmTBI results in a loss of DAergic innervation in the MSA, which is a region of cholinergic nuclei that project to the hippocampus. Changes in DA innervation will be determined by a novel florescence-activated synaptosome sorting (FASS) process to quantitate hTH-GFP-positive synaptosomes in the MSA. To determine if the loss of DAergic innervation of cholinergic systems is functionally significant, we will use microdialysis to measure hippocampal ACh levels evoked by electrical stimulation of the medial forebrain bundle. If successful, this project will demonstrate the use of contemporary and novel methods to evaluate the degree and consequences of DAergic dysconnectivity after TBI.

所有严重程度的创伤性脑损伤 (TBI) 都可能导致认知、行为、情绪、 和身体机能。 TBI后认知功能的恢复是一个动态过程，其中认知功能的改变 神经递质系统不可能孤立地发生。大量研究表明， 内侧隔膜和 Broca 对角线带（内侧隔膜区域 [MSA]）区域的多巴胺能 (DA) 神经支配 胆碱能神经元密集的区域会影响海马乙酰胆碱 (ACh) 的释放。此举的目标 R21 拨款用于评估 TBI 引起的多巴胺能/胆碱能完整性的轻度重复性变化 使用现代工具进行连接，包括带有网络分析的扩散 MRI 纤维束成像、转基因 人酪氨酸羟化酶 GFP 表达大鼠，以及荧光激活突触体分选 (FASS) 分析。总体假设是 TBI 导致 DA 光纤连接丢失，包括 DAergic MSA 的神经支配，导致胆碱能缺陷。目标 1 将确定重复轻度的影响 使用高清光纤跟踪进行流体冲击 TBI (rmTBI) 对黑质纹状体通路连接的影响 结合网络拓扑分析。 hTH-GFP 大鼠的免费免疫组织化学将 与成像纤维束成像相比，增强了 DA 回路的特异性。目标 2 将确定 rmTBI 是否结果 MSA 中 DAergic 神经支配的丧失，这是投射到 海马体。 DA 神经支配的变化将由新型荧光激活突触体决定 分选 (FASS) 过程对 MSA 中的 hTH-GFP 阳性突触体进行定量。来判断是否丢失 胆碱能系统的DAergic神经支配具有重要的功能，我们将使用微透析来测量 电刺激内侧前脑束引起的海马乙酰胆碱水平。如果成功的话，这个项目 将展示如何使用当代和新颖的方法来评估的程度和后果 TBI 后 DAergic 连接失调。