Central Rhythmogenesis and Behavior

描述（由申请人提供）：本项目将重点研究n -甲基- d -天冬氨酸（NMDA）谷氨酸受体和神经元间隙连接协同作用以确定脑电偶联网络内活动的时空动态的假设。这一假设将在小脑的下橄榄区进行测试，下橄榄区是成年人大脑中电突触密度最高的一个主要传入区。我们实验室之前的工作表明，NMDA受体激活诱导下橄榄神经元膜电位的高阈值振荡，并且由connecin36介导的神经元间隙连接对下橄榄神经元连贯振荡的连续性和强度至关重要。有4个目标。目的1将确定NMDA受体是否通过作用于神经元间隙连接来调节耦合网络中的电一致性和节律。目的2将确定NMDA受体是否在体外形成电偶联的空间动力学。目的3将确定下橄榄中NMDA受体上调与缺氧诱导的小脑神经元死亡之间是否存在对应关系。目的4将确定阻断NMDA受体在下橄榄中的单独功能，还是阻断神经元间隙连接，是否会防止缺氧后小脑中延迟的神经元死亡。这些目标将通过多电极记录、多束多光子显微镜和基因转移来实现，以表达下橄榄中具有显性负作用的蛋白质和RNA抑制剂序列。近年来，下橄榄NMDA受体的上调和浦肯野细胞的死亡与婴儿猝死综合征独立相关。这项研究将确定这些临床相关现象是如何相互关联的。本应用程序中提出的研究将提供有关下橄榄特定脑区神经元振荡机制的重要信息，以及该脑区引发小脑神经元死亡的病理活动的潜力。这些研究的结果不仅有助于我们对大脑功能的一般理解，而且可能与婴儿猝死综合症有关，这是大脑累积缺氧损伤的悲惨结果。这些研究的长期目标是确定大脑正常和病理振荡的细胞生物学和神经元集合机制。

DESCRIPTION (provided by applicant): This project will focus on the hypothesis that N-methyl-D-aspartate (NMDA) glutamate receptors and neuronal gap junctions act concertedly to determine the spatio-temporal dynamics of activity within electrically coupled networks in brain. The hypothesis will be tested in the inferior olive, a major afferent of the cerebellum that has the highest density of electrical synapses in the adult brain. Previous work from our laboratory showed that NMDA receptor activation induces high-threshold oscillations in membrane potential in inferior olive neurons and that neuronal gap junctions mediated by connexin36 are critical for the continuity and strength of coherent oscillations in the inferior olive. There are 4 aims. Aim 1 will determine whether NMDA receptors regulate electrical coherence and rhythm within a coupled network by acting on neuronal gap junctions in vivo. Aim 2 will determine whether NMDA receptors shape the spatial dynamics of electrical coupling in vitro. Aim 3 will determine whether there is a correspondence between NMDA receptor upregulation in the inferior olive and hypoxia-induced death of cerebellar neurons. Aim 4 will determine whether the block of NMDA receptor function in the inferior olive alone, or with neuronal gap junctions, will prevent delayed neuronal death in the cerebellum after hypoxia. These aims will be carried out with a combination of multielectrode recording, multibeam multiphoton microscopy, and gene transfer to express proteins with dominant-negative effect and RNA inhibitor sequences in the inferior olive. Recently, the upregulation of the NMDA receptor in the inferior olive and the death of Purkinje cells were independently related to sudden infant death syndrome. The research will establish how these clinically-relevant phenomena are related to one another. PUBLIC HEALTH RELEVANCE The studies proposed in the present application will provide important information about the mechanisms of neuronal oscillation in a specific brain region named the inferior olive, and the potential for pathological activity in that brain area for triggering neuronal death in the cerebellum. The results of these studies will be useful not only for our general understanding of brain function but may be relevant to the sudden infant death syndrome, a tragic result of cumulative hypoxic damage to the brain. The long term goal of these studies is to determine the cell biological and neuronal ensemble mechanisms of normal and pathological oscillations in the brain.