Mechanisms of respiratory long-term facilitation

描述(申请人提供)：可塑性是神经系统的一个重要特征，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，但我们对导致任何形式的呼吸道可塑性的机制的了解是不完整的。在这份修订后的竞争性更新申请中，将继续研究引起膈神经长期易化的细胞机制，这是急性间歇性低氧诱导的呼吸可塑性的重要模型。在大鼠模型中，将使用多种实验方法来研究长期促进的机制，包括麻醉大鼠的神经记录、非麻醉大鼠的通气量测量、RNA干扰的应用、调节在呼吸可塑性中发挥作用的潜在重要基因的新方法、固定组织中的蛋白质分析和荧光方法以确定重要分子的表达变化，如活性氧物种。使用这些方法，将在本申请中检验五个假设，以进行竞争更新。首先，在目标1中，将探索蛋白质NADPH氧化酶和蛋白磷酸酶2A作为长期促进的关键调节因子的假设。下一步，将测试不同的细胞机制引起长时间促进膈神经活动的可能性，而膈神经的长期促进只是其中之一。在目标2中，我们将研究其中的两种机制，分别命名为“Q”和“S”通路。在最后三个目标中，将检验假设：Q和S通路通常相互抑制(目标3)，但动物具有在Q和S通路之间转换的能力(目标4)，或者它们可以同时参与这两个通路(目标5)。在实现呼吸神经活动便利化方面的这种灵活性可能会赋予个体在一生中对诸如疾病发作等生理挑战做出反应的灵活性。对导致膈运动易化的细胞机制的详细了解将指导开发新的治疗策略来治疗严重的呼吸机控制障碍，包括脊髓损伤或运动神经元病(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。 公共卫生相关性：一些呼吸机控制障碍，如婴儿猝死综合征(SID)或颈椎损伤患者的呼吸功能不全，或ALS等神经退行性疾病，都是灾难性的。其他一些疾病，如阻塞性睡眠呼吸暂停，对公众健康有深远的影响。我们的目标是在对呼吸可塑性的详细了解的基础上，开发针对呼吸控制障碍的新的治疗策略，呼吸可塑性是呼吸控制系统的一个关键方面，直到最近几年才得到重视。

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.