Mechanisms of respiratory long-term facilitation

描述（由申请人提供）：可塑性是神经系统的重要特征，包括控制呼吸的神经系统。尽管它具有潜在的生物学和临床意义，但我们对引起任何形式的呼吸可塑性的机制的理解是不完整的。在这一竞争性更新的修订申请中，将继续研究引起膈长期促进的细胞机制，膈长期促进是急性暴露于间歇性缺氧诱导的呼吸可塑性的重要模型。在大鼠模型中，长期促进的机制将通过多种实验方法进行研究，包括麻醉大鼠的神经记录，未麻醉大鼠的通气测量，RNA干扰的应用，调节呼吸可塑性中潜在重要基因的新方法，蛋白质分析和荧光方法在固定组织中确定重要分子（如活性氧）的表达变化。使用这些方法，五个假设将测试在这个应用程序的竞争性更新。首先，在Aim 1中，将探讨蛋白质NADPH氧化酶和蛋白质磷酸酶2A作为长期促进的关键调节因子的假设。接下来，将测试不同的细胞机制引起膈神经活动持久促进的可能性，其中膈神经长期促进只是其中之一。在Aim 2中，我们将研究其中的两种机制，即膈运动促进的“Q”和“S”通路。在最后三个目标中，假设将被测试：Q和S通路通常相互抑制（目标3），但动物有能力在Q和S通路之间转换膈运动促进（目标4），或者它们可以同时参与两种途径（目标5）。这种实现呼吸神经活动促进的灵活性可能赋予个体在一生中应对生理挑战（如疾病发作）时的灵活性。对引起膈运动促进的细胞机制的详细了解将指导严重通气控制障碍的新治疗策略的发展，包括脊髓损伤或运动神经元疾病（ALS）患者的阻塞性睡眠呼吸暂停和呼吸功能不全。因此，我们研究的一个重要的潜在目标是确定调节PMF的分子作为潜在的治疗靶点。

DESCRIPTION (provided by applicant): Plasticity is an important feature of neural systems, including the neural system controlling breathing. Despite its potential biological and clinical significance, our understanding of mechanisms giving rise to any form of respiratory plasticity is incomplete. In this revised application for competitive renewal, investigations will be continued concerning cellular mechanisms giving rise to phrenic long-term facilitation, an important model of respiratory plasticity induced by acute exposure to intermittent hypoxia. In a rat model mechanisms of long- term facilitation will be investigated using multiple experimental approaches, including nerve recordings in anesthetized rats, measurements of ventilation in unanesthetized rats, application of RNA interference, a novel method of regulating potentially important genes that play a role in respiratory plasticity, protein analysis and fluorescent methods in fixed tissues to determine expression changes in important molecules, such as reactive oxygen species. Using these approaches, five hypotheses will be tested in this application for competitive renewal. First, in Aim 1, the hypothesis that the proteins NADPH oxidase and protein phosphatase 2A function as key regulators of long term facilitation will be explored. Next, the possibility that distinct cellular mechanisms give rise to long-lasting facilitation of phrenic nerve activity, of which phrenic long term facilitation is only one, will be tested. In Aim 2, two of these mechanisms will be investigated, designated the "Q" and "S" pathways to phrenic motor facilitation. In the final three aims, the hypotheses will be tested that the Q and S pathways normally suppress one another (Aim 3), but that animals have the capacity to shift between the Q and S pathways phrenic motor facilitation (Aim 4), or that they can engage both pathways at the same time (Aim 5). Such flexibility in achieving facilitation of respiratory nerve activity may impart flexibility as an individual responds to physiological challenges throughout life, such as the onset of disease. A detailed understanding of cellular mechanisms giving rise to phrenic motor facilitation will guide the development of novel therapeutic strategies for severe ventilatory control disorders, including obstructive sleep apnea and respiratory insufficiency in patients with spinal injury or motor neuron disease (ALS). Thus, an important underlying goal of our research is to identify molecules regulating PMF as potential therapeutic targets. PUBLIC HEALTH RELEVANCE: Some ventilatory control disorders such as sudden infant death syndrome (SIDS) or respiratory insufficiency in patients with cervical spinal injury or neurodegenerative diseases like ALS are catastrophic. Others, such as obstructive sleep apnea, have profound consequences for public health. Our goal is to develop novel therapeutic strategies for ventilatory control disorders based on a detailed understanding of respiratory plasticity, a critical aspect of the ventilatory control system that has become appreciated only in recent years.