Airway-Central Nervous System Control

描述（由申请人提供）：慢性气道疾病，如支气管哮喘和慢性阻塞性支气管炎，具有炎症、对各种吸入剂的高反应性和气道狭窄的显著特征。尽管这两种疾病导致了巨大的发病率和社会成本，但涉及气道高反应性的中枢神经系统机制仍然知之甚少。在本研究之前的资助周期中，我们已经描述了参与兴奋性输入从呼吸道传递到孤束核（NTS）神经元的主要神经化学物质和受体亚型；从这些二级感觉细胞到气道相关迷走神经节前运动神经元（avpn）；从avpn回到气道。作为这项工作的自然延续，我们现在专注于调节胆碱能驱动到气道的抑制途径。神经解剖学研究将确定抑制性gaba能、儿茶酚胺能或5 -羟色胺能细胞群和avpn之间的正常神经回路。在这些研究中，逆行示踪将用于确定向气管投射的avpn。双重或三重标记免疫细胞化学将用于同时定位神经递质，它们的受体和avpn。将使用光学显微镜、共聚焦显微镜和电子显微镜检查组织。蛋白水平将通过免疫印迹法测定。在生理研究中，我们将微注射摄取抑制剂、特异性激动剂或拮抗剂到鼻侧歧见核（rNA， avpn丰富的地方），以确定特异性抑制性神经递质及其受体在基础和反射诱导的气管张力和气道阻力变化中的功能作用。随后，我们将验证一个假设，即在致敏动物中反复暴露于过敏原会引起中枢抑制影响的形态和生理变化，从而导致从抑制性向兴奋性传递的转变。这些变化导致avpn的高兴奋状态和气道的高反应性。这些研究的结果将为气道的神经控制提供必要的知识，并将支持开发针对中枢神经系统治疗气道疾病的新型药物策略。

DESCRIPTION (provided by applicant): Chronic airway diseases such as bronchial asthma and chronic obstructive bronchitis share the salient features of inflammation, hyperresponsiveness to various inhalants, and airway narrowing. Although these two conditions result in enormous morbidity and social cost, the central nervous system mechanisms involved in airway hyperreactivity remain poorly understood. In the prior funding cycle of this proposal we have characterized the primary neurochemical(s) and receptor subtypes involved in transmission of excitatory inputs from the respiratory tract to the nucleus tractus solitarius (NTS) neurons; from these second order sensory cells to airway-related vagal preganglionic motor neurons (AVPNs); and from AVPNs back down to the airways. As a natural continuation of this work, we now focus on inhibitory pathways that regulate cholinergic drive to the airways. Neuroanatomical studies will define the normal neural circuitry between inhibitory GABAergic, catecholaminergic, or serotonergic cell groups and AVPNs. In these studies, retrograde tracing will be used to define AVPNs projecting to the trachea. Dual or triple labeling immunocytochemistry will be used to simultaneously locate neurotransmitters, their receptors, and AVPNs. Tissues will be examined using light microscopy, confocal microscopy, and electron microscopy. Protein levels will be measured by Western blotting. In physiological studies, we will microinject uptake inhibitors, specific agonists, or antagonists into the rostral nucleus ambiguus (rNA, where AVPNs are abundant), to define the functional roles of specific inhibitory neurotransmitters and their receptors on basal and reflex-induced changes in tracheal tone and airway resistance. Subsequently, we will test the hypothesis that repeated exposure to allergens in sensitized animals induces morphological and physiological changes in central inhibitory influences, resulting in a shift from inhibitory to excitatory transmission. These changes lead to a hyperexcitable state of AVPNs and to airway hyperreactivity. The results of these studies will provide necessary knowledge in the neural control of the airways and will support the development of novel pharmaceutical strategies which target the central nervous system for the treatment of airway disorders.