The role of Dbx1-derived medullary neurons for rhythm generation in the intact respiratory network

Dbx1 衍生的髓质神经元在完整呼吸网络中节律生成中的作用

• 批准号: 9190066
• 负责人: Nathan Andrew Baertsch
• 金额: $ 5.61万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2019-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9190066
• 关键词: Animals; Area; Basic Science; Behavior; Biological Neural Networks; Brain Stem; Breathing; Calcium; Cells; Central Nervous System Diseases; Complex; Coupled; Data; Development; Electrophysiology (science); Frequencies; Generations; Goals; Imaging Techniques; In Vitro; Lesion; Life; Mammals; Mental Depression; Modeling; Mus; Neurons; Neurotransmitters; Phase; Population; Preparation; Refractory; Respiration; Role; Sleep; Slice; Techniques; Testing; Theoretical Studies; Time; Transgenic Mice; base; clinically significant; excitatory neuron; expiration; in vivo; insight; interest; neural circuit; novel; optogenetics; presynaptic; receptor expression; relating to nervous system; research study; respiratory; synaptic depression; transcription factor

1: PROJECT SUMMARY Breathing is a complex behavior that is fundamental for life in all mammals. Disturbances in the function and coordination of breathing are common in many disorders of the central nervous system. Thus, the study of specific neural populations that underlie this behavior is not only of great basic science interest, but holds high clinical significance. Lesion experiments and in-vitro studies using transverse brainstem slices have defined the minimal circuitry that is necessary and sufficient for the inspiratory phase of breathing, a small “kernel” of neurons in the ventrolateral medulla termed the preBötzinger Complex (preBötC). Excitatory neurons derived from cells expressing the transcription factor Dbx1 are thought to form the rhythmogenic “core” of the preBötC. However, a “refractory period” for Dbx1 stimulation following each breath limits the ability these neurons to drive a high frequency rhythm in-vitro. The role of this specific population of neurons in controlling the wide range of breathing frequencies common in-vivo is unknown. In this project we will use novel in-vivo and in-vitro approaches conducted in parallel to investigate the role of Dbx1 neurons in the generation of inspiration when embedded in the wider medullary network. Based on our preliminary data, we hypothesize that the inspiratory neural network functions as a distributed column, and is not limited to a defined “core” region. Inhibition of excitatory Dbx1 neurons effectively drives the inspiratory rhythm through post-inhibitory rebound. And, the refractory period for Dbx1 can be reduced in the distributed inspiratory network to allow faster breathing frequencies by modulating mechanisms of short-term synaptic depression. These hypotheses will be tested using powerful optogenetic, electrophysiological, pharmacological and imaging techniques in anesthetized and freely behaving mice (Aim1) and in a novel horizontal brainstem slice preparation that preserves the wider medullary network bilaterally (Aim2). We expect that integration of these preparations will provide a unique perspective to examine issues that remain unresolved in the field of respiratory rhythm generation.

1：项目概要 呼吸是一种复杂的行为，是所有哺乳动物生命的基础。功能障碍和 呼吸协调在许多中枢神经系统疾病中很常见。因此，研究 这种行为背后的特定神经群体不仅具有重大的基础科学意义，而且具有很高的价值 临床意义。使用横向脑干切片的病变实验和体外研究已经定义了 呼吸的吸气阶段所必需且足够的最小电路，一个小的“内核” 腹外侧髓质中的神经元称为前 Bötzinger 复合体 (preBötC)。兴奋性神经元衍生 来自表达转录因子 Dbx1 的细胞被认为形成了 preBötC 的节律“核心”。 然而，每次呼吸后 Dbx1 刺激的“不应期”限制了这些神经元的能力 在体外驱动高频节律。这种特定神经元群在控制广泛的神经元中的作用 体内常见的呼吸频率范围尚不清楚。在这个项目中，我们将使用新颖的体内和体外 并行进行的方法研究 Dbx1 神经元在灵感产生中的作用 嵌入更广泛的髓质网络中。根据我们的初步数据，我们假设吸气 神经网络充当分布式列，并且不限于定义的“核心”区域。抑制 兴奋性 Dbx1 神经元通过抑制后反弹有效驱动吸气节律。并且， 分布式吸气网络中 Dbx1 的不应期可以缩短，从而加快呼吸速度 通过短期突触抑制的调节机制来调节频率。这些假设将被检验 在麻醉和麻醉中使用强大的光遗传学、电生理学、药理学和成像技术 自由行为的小鼠（Aim1）和一种新颖的水平脑干切片制剂，可以保留更广泛的 双侧髓质网络（目标2）。我们期望这些准备工作的整合将提供独特的 的角度来研究呼吸节律产生领域中尚未解决的问题。