Role of Dendritic Ca2+ Transients in Respiratory Rhythm Generation

描述（由申请人提供）：我们研究哺乳动物呼吸节律的产生和调节。呼吸是脊椎动物的一项重要行为，它调节气体交换以支持新陈代谢。对哺乳动物来说，可靠而有力的呼吸节奏是必不可少的。患有睡眠呼吸暂停、早产呼吸暂停、先天性中枢性低通气综合征、中枢性肺泡低通气综合征、过度通气综合征、Rett综合征以及婴儿猝死综合征等疾病的人不能维持正常的呼吸节奏，会导致严重的不良健康后果，甚至死亡。各种神经退行性疾病，如帕金森氏病、多系统萎缩和肌萎缩侧索硬化症，都与睡眠呼吸障碍有关，我们假设这是由控制呼吸的大脑区域的神经元丧失造成的。如果要理解正常和病理条件下的呼吸，必须揭示呼吸节律发生的部位和机制。在体外实验中，脑干中的PreB"tzinger Complex （PreB" tC）神经元是呼吸节律产生的基础，在体内对清醒的成年大鼠的呼吸至关重要。虽然我们的最终目标是解释完整哺乳动物，特别是健康和疾病的人类呼吸节律的产生，但在体内条件下，检查基本细胞/网络机制的必要研究目前是不可能的。在这个提议中，我们将利用一个有效的和强大的体外呼吸模型，有节奏的髓质切片产生呼吸相关的运动输出，来研究preB”tC神经元的细胞特性，并推进我们对呼吸节律发生的理解。我们将使用最先进的技术，如钙成像和钙溶出来测试假设：钙离子瞬态在决定preB”tC神经元的动态特性中起着关键作用，这被广泛认为在呼吸节律发生中起着必要的作用。我们提出两个具体目标。目的1：我们将确定preB”tC神经元钙瞬态在颞叶和体树突中的分布。目的2：我们将确定钙瞬态对这些关键神经元动态特性的影响。通过详细介绍神经元内钙瞬态如何影响呼吸节律，我们将大大提高我们对呼吸神经控制的认识。这些研究应该对我们理解人类在健康和疾病中的呼吸做出根本性的贡献。

DESCRIPTION (provided by applicant): We study the generation and regulation of respiratory rhythm in mammals. Breathing is a remarkable behavior in vertebrates that regulates gas exchange to support metabolism. A reliable and robust rhythm is essential for breathing in mammals. The failure to maintain a normal breathing rhythm in humans suffering from disorders such as sleep apnea, apnea of prematurity, congenital central hypoventilation syndrome, central alveolar hypo- ventilation syndrome, hyperventilation syndrome, Rett syndrome, and perhaps sudden infant death syndrome, leads to serious adverse health consequences, even death. Various neurodegenerative diseases, such as Parkinson's disease, multiple systems atrophy and amyotrophic lateral sclerosis, are associated with sleep disordered breathing that we hypothesize results from the loss of neurons in brain areas controlling respiration. If breathing is to be understood in normal and in pathological conditions, the site(s) and mechanisms for respiratory rhythmogenesis must be revealed. PreB"tzinger Complex (preB"tC) neurons in the brainstem underlie respiratory rhythm generation in vitro and are essential for breathing in awake adult rats in vivo. While our ultimate goal is to explain the generation of respiratory rhythm in intact mammals, in particular humans in health and disease, studies necessary to examine basic cellular/network mechanisms are presently impossible under in vivo conditions. In this proposal we will exploit a validated and powerful in vitro model of breathing, the rhythmic medullary slice generating a respiratory-related motor output, to investigate cellular properties of preB"tC neurons and advance our understanding of respiratory rhythmogenesis. We will use state of the art techniques such as calcium imaging and calcium uncaging to test the hypothesis: Calcium ion transients play a critical role in determining the dynamic properties of preB"tC neurons that are widely accepted to play a necessary role in respiratory rhythmogenesis. We propose 2 SPECIFIC AIMS. AIM 1: We will determine the temporal and somatodendritic distribution of calcium transients in preB"tC neurons. AIM 2: We will determine the effects of calcium transients on the dynamic properties of these key neurons. By detailing how intraneuronal calcium transients affect respiratory rhythm we will significantly improve our knowledge of neural control of breathing. These studies should make fundamental contributions to our understanding of breathing in humans in health and disease. PUBLIC HEALTH RELEVANCE: In humans, continuous breathing from birth is essential to life and requires that the nervous system generate a reliable and robust rhythm that drives inspiratory and expiratory muscles. The proposed studies will significantly advance our understanding of the neural mechanisms generating respiratory rhythm and shed light on human disorders of breathing.