A tale of two synapses: The development of neurotransmitter phenotype in motor ne

描述（由申请人提供）：两个突触的故事：运动神经元中神经递质表型的发育。 虽然运动神经元在神经肌肉接头处释放乙酰胆碱已经知道了60年，但越来越多的证据表明运动神经元也在其他神经元的突触处释放兴奋性氨基酸递质。最近的几项研究提供的证据表明，运动神经元释放多种神经递质在空间上隔离的方式之间的不同类型的突触，它们使-神经肌肉接头在外周和脊髓中的神经元间突触。我们实验室和其他人最近发表的工作表明，在从胚胎中分离的运动神经元培养物中，在不与肌肉细胞接触的情况下生长，培养物中的兴奋性神经传递完全通过谷氨酸，没有检测到胆碱能神经传递。最近可用的光遗传学小鼠模型，允许可逆的，实时的和细胞自主的光激活的乙酰胆碱释放神经元提供了一个很好的工具，研究运动神经元中神经递质表型的发展。拟议研究的目的是使用电生理学，共聚焦成像和光遗传学方法与运动神经元在培养和脊髓切片中生长，以确定由运动神经元形成的突触在其他神经元上的神经递质表型，并研究如何与肌肉细胞接触，神经肌肉接头的形成，以及可能的乙酰胆碱酯酶影响神经递质释放。深入了解神经元是如何被引导在不同的靶点上形成不同类型的突触的，包括发展多种神经递质的空间分离释放，对于理解神经元发育至关重要。运动神经元使两类突触在结构、功能和位置上有明显区别，是研究突触发育差异的理想模型系统。了解与肌肉的相互作用如何完成运动神经元的发育，将有助于深入了解神经肌肉疾病的病理生理学，包括发育性运动神经元疾病，如脊髓性肌萎缩症和肌营养不良症。此外，随着越来越多的研究人员探索使用分化的多能细胞来替代因疾病或损伤而失去的运动神经元，对运动神经元分化和突触生理学的全面了解将对推进该研究至关重要。这个项目是理想的R15支持作为特拉华州州立大学是一个历史上黑人，主要是本科院校，约80%的非洲裔美国人入学。资助这项研究将增加少数民族本科生和研究生通过参加重要的科学研究直接体验科学过程的机会。

DESCRIPTION (provided by applicant): A tale of two synapses: the development of neurotransmitter phenotype in motor neurons. While it has been known for 60 years that motor neurons release acetylcholine at neuromuscular junctions, evidence has been accumulating that motor neurons also release an excitatory amino acid transmitter at synapses on other neurons. Several recent studies provide evidence that motor neurons release multiple neurotransmitters in a spatially segregated way between the distinct types of synapses they make - neuromuscular junctions in the periphery and inter- neuronal synapses in the spinal cord. Recently published work from our lab and others has shown that in cultures of motor neurons isolated from embryos and grown in the absence of contact with muscle cells, excitatory neurotransmission in the culture is entirely through glutamate with no detectable cholinergic neurotransmission. The recent availability of an optogenetic mouse model that allows reversible, real-time and cell-autonomous photo-activation of acetylcholine-releasing neurons provides an excellent tool to investigate the development of neurotransmitter phenotype in motor neurons. The objective of the proposed study is to use electrophysiology, confocal imaging and optogenetic approaches with motor neurons grown in culture and in spinal cord slices to determine the neurotransmitter phenotype of synapses formed by motor neurons on other neurons, and investigate how contact with muscle cells, the formation of neuromuscular junctions, and possibly acetylcholinesterase influence the neurotransmitter released. Insight into how neurons are guided to make different types of synapses on different targets, including developing spatially segregated release of multiple neurotransmitters, is crucial for understanding neuronal development. Motor neurons, which make two types of synapses clearly differentiated in structure, function and location, are an ideal model system in which to investigate differential synaptic development. Understanding how interaction with muscle completes the development of motor neurons will lead to insights into the pathophysiology of neuromuscular disorders including developmental motor neuron diseases such as spinal muscular atrophy and muscular dystrophy. In addition, as more researchers explore the use of differentiated pluripotent cells for potential replacement of motor neurons lost to disease or injury, a complete understanding of motor neuron differentiation and synaptic physiology will be crucial to advancing that research. This project is ideal for R15 support as Delaware State University is an Historically Black, predominantly undergraduate institution with approximately 80% African-American enrollment. Funding this research will increase opportunities for minority undergraduate and graduate students to directly experience the scientific process by taking part in important scientific research.