Effects of TrkB Activation on Abnormalities in Neocortical FS Interneurons

TrkB 激活对新皮质 FS 中间神经元异常的影响

• 批准号: 9231510
• 负责人: David Allan Prince
• 金额: $ 34.42万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2018-07-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9231510
• 关键词: Affect; Aftercare; Agonist; Anatomy; Animals; Antibodies; Area; Biological Neural Networks; Brain; Brain Diseases; Brain-Derived Neurotrophic Factor; Cells; Cerebral cortex; Chemicals; Chronic; Cognition; Cognitive; Computer software; Computers; Conflict (Psychology); Confocal Microscopy; Conotoxin; Data; Defect; Dependence; Development; Electroencephalography; Engineering; Epilepsy; Failure; Frequencies; Generations; Glutamates; Goals; Growth; Hot Spot; Human; Image; Imaging Techniques; In Vitro; Incidence; Individual; Injury; Interneuron function; Interneurons; Kinetics; Lasers; Lead; Length; Maintenance; Maps; Measures; Military Personnel; Modeling; Mus; Nerve; Nerve Growth Factors; Neurons; Neurotrophic Tyrosine Kinase Receptor Type 2; Output; Partial Epilepsies; Patch-Clamp Techniques; Pharmaceutical Preparations; Phosphotransferases; Physiologic pulse; Play; Post-Traumatic Epilepsy; Presynaptic Terminals; Process; Property; Proto-Oncogene Proteins c-akt; Public Health; Pyramidal Cells; Rattus; Rodent; Role; Saline; Scanning; Sensory; Sensory Disorders; Severe Concussions; Slice; Staining method; Stains; Structural defect; Structure; Testing; Trauma; Traumatic Brain Injury; Traumatic injury; Tropomyosin; biocytin; chemical release; experimental study; gamma-Aminobutyric Acid; hippocampal pyramidal neuron; improved; improved functioning; induced pluripotent stem cell; injured; light microscopy; microscopic imaging; motor disorder; neocortical; neuronal cell body; presynaptic; prevent; prophylactic; public health relevance; receptor; small molecule; transmission process

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) results in abnormalities in cerebral cortex and disorders of sensory and motor function, cognitive abnormalities and epilepsy. The potential development of epilepsy by the large number of individuals, who have survived severe concussive injury during recent conflicts, emphasizes the need for understanding the underlying pathophysiological processes and the development of prophylactic strategies (Garga and Lowenstein, 2006). A goal of this project is to obtain basic information on approaches that may improve or prevent such posttraumatic abnormalities. Injury to nerve cells that release the chemical transmitter GABA is a common result of TBI. Improvement in the structure and function of these inhibitory cells, "interneurons", may prevent some of the consequences of injury, including epilepsy. Preliminary results show that fast-spiking (FS) inhibitory interneurons, the most common type of interneuron in cortex, have abnormal nerve processes and defects in releasing GABA in areas of cortical injury produced by partially cutting connections with surrounding brain ("undercuts"). Undercut cortex becomes hyperexcitable due to this and other defects and often generates epileptiform electrical activity that resembles EEG activity in human focal epilepsy. A neurotrophic protein BDNF, and its receptor TrkB, are important for development, growth and maintenance of interneurons, and are reduced in the injured area, leading to the hypothesis that TrkB activation may correct abnormalities in FS or other interneurons and improve function in the injured cortex. To test this hypothesis, undercuts will be made in anesthetized rodents, and animals treated with a newly- engineered "small" molecule, LM22A-4, that enters the brain and activates the TrkB receptor. After treatment for ~2 weeks, rodents are re-anesthetized, and standard in vitro slice and patch clamp techniques used to obtain recordings from single interneurons and excitatory cells in areas of injury from drug-treated animals and saline controls. Activities of individual nerve cells and large groups of neurons ("field potentials") will be analyzed with appropriate software. Laser-activated release of the excitatory chemical transmitter, glutamate, will be used to map changes in excitatory and inhibitory connections in neural networks within individual slices, and effects of chronic LM22A-4 treatment. The structure of single cells will be measured after filling them with a marker called biocytin, staining slices with antibodies, and using computer-controlled microscopic imaging techniques, including light and confocal microscopy. The aims of these experiments are to determine whether activation of the TrkB receptor will improve the anatomical and functional abnormalities in FS interneurons, restore normal release of GABA and favorably affect nerve circuits in the injured cortex.

描述（由申请人提供）：创伤性脑损伤（TBI）导致脑皮质和感觉和运动功能，认知异常和癫痫病的异常。在最近的冲突期间在严重的脑震荡中幸存下来的大量个体癫痫的潜在发展，强调需要理解潜在的病理生理过程和预防策略的发展（Garga and Lowenstein，2006年）。该项目的一个目标是获取有关可能改善或阻止这种创伤后异常的方法的基本信息。释放化学发射器GABA的神经细胞的损伤是TBI的常见结果。这些抑制细胞的结构和功能改善“中间神经元”可能会阻止损伤的某些后果，包括癫痫。初步结果表明，在皮质中最常见的中间神经元类型的快速刺激性（FS）抑制性中间神经元具有异常的神经过程和缺陷在释放GABA的皮质损伤区域中，通过部分切割与周围大脑的连接所产生的皮质损伤区域（“底盘”）。由于这种缺陷和其他缺陷，底切底皮层变得过度兴奋，并且通常会产生类似于人类局灶性癫痫中脑电图活性的癫痫样电活动。神经营养蛋白BDNF及其受体TRKB对于中间神经元的发育，生长和维持至关重要，并且在受伤区域减少了，导致假设TRKB激活可能纠正FS或其他中间神经元的异常，并改善受伤的功能皮质。为了检验这一假设，将在麻醉啮齿动物中制造底切，并用新设计的“小”分子LM22A-4进行处理，该动物进入大脑并激活TRKB受体。治疗约2周后，重新安装啮齿动物，并在药物处理的动物和盐水对照组中从单个神经元和兴奋性细胞中获取记录的标准体外切片和贴片夹技术。单个神经细胞的活动 将使用适当的软件分析大量神经元（“现场电位”）。激光激活的兴奋性化学发射器谷氨酸的释放将用于绘制单个切片中神经网络中兴奋性和抑制性连接的变化，以及慢性LM22A-4处理的影响。单个细胞的结构将在用称为生物细胞的标记填充后测量，用抗体染色切片，并使用计算机控制的显微镜成像技术，包括光和共聚焦显微镜。这些实验的目的是确定TRKB受体的激活是否会改善FS中间神经元中的解剖和功能异常，恢复GABA的正常释放，并有利地影响受伤的皮质中的神经回路。