Anatomy of Neuroendocrine Peptide Pathways in Brain

项目总结（见说明）：促肾上腺皮质激素释放因子（CRF）家族的信号分子在影响综合内分泌，自主神经和情感/行为反应的压力发挥重要的作用和相互作用。它包括四种配体（CRF和尿皮质素（Ucn）1-3），其通过两种G蛋白偶联受体（CRFR 1和CRFR 2）中的任一种或两种发出信号。中枢自主神经系统（CAS）是一个由中枢神经系统细胞群组成的相互连接的网络，包括应激相关的CRF/Ucn作用的敏感部位，但它们内部CRF配体和受体信号传导的基础，以及在塑造个体应激适应模式中提供CRFR 1和R2依赖性机制之间相互作用的回路，都还不清楚。我们将与该计划的其他组成部分合作，以验证免疫学和分子遗传学工具，以确定CRFR如何分布在CAS组件中，以及它们与含配体的末端字段的关系。证据表明，功能表现的配体-受体的“错配”可能会适应突触前CRFR的表达，新的内源性Ucn形式和/或全身作用的集中管理的肽将被追求。第二个主要目标是确定扩展回路，该扩展回路提供CRFR相互作用，以调节（1）控制垂体-肾上腺轴激活的下丘脑神经元和（2）杏仁核中介导与焦虑相关的情感行为的细胞群的应激诱导激活。将采用转基因CRFR报告小鼠来鉴定可能参与这些功能的应激敏感性、携带受体的内源性和外源性细胞群。然后将使用组合的组织化学和轴突运输方法来逐步解开CRFR 1和-R2机制可能相互作用以形成感兴趣的终点和CRFR配体在其中的分布的候选电路。最后，位点特异性的，有条件的基因靶向方法将被用来测试在压力诱导的垂体肾上腺激素分泌和焦虑的行为措施的牵连电路的关键节点的功能参与。结果预计将提供一个系统水平的角度来看，中央CRF系统的压力反应的关键方面的作用，并归因于该系统在压力适应的综合能力的严格测试。

PROJECT SUMMARY (See instructions): The corticotropin-releasing factor (CRF) family of signaling molecules plays important and interactive roles in effecting integrated endocrine, autonomic and affective/behavioral responses to stress. It includes four ligands (CRF and urocortin (Ucn) 1-3) that signal though either or both of two G protein-coupled receptors (CRFRl and CRFR2). An interconnected network of CNS cell groups, termed the central autonomic system (CAS), comprises sensitive sites of stress-related CRF/Ucn action, but neither the bases for CRF ligandreceptor signaling within them, nor the circuitry that provides for documented interactions between CRFR1 - and R2-dependent mechanisms in sculpting individual modes of stress adaptation, are well understood. We will work with other components of the Program to validate immunologic and molecular genetic tools with which to determine how CRFRs are distributed in CAS components, and their relation to ligand-containing terminal fields. Evidence that functional manifestations of the ligand-receptor "mismatch" may be accommodated by presynaptic CRFR expression, novel endogenous Ucn forms and/or systemic effects of centrally administered peptides will be pursued. A second major goal is to define the extended circuitries that provide for CRFR interplay in regulating stress-induced activation of (1) hypothalamic neurons that govern activation of the pituitary-adrenal axis, and (2) cell groups in the amygdala that mediate affective behaviors related to anxiety. Transgenic CRFR reporter mice will be employed to identify stress-sensitive, receptor-bearing intrinsic and extrinsic cell groups potentially involved in these functions. Combined histochemical and axonal transport methods will then be used to progressively unravel candidate circuitries by which CRFR1 and -R2 mechanisms may interact to shape the endpoints of interest and the disposition of CRFR ligands within them. Finally, site-specific, conditional gene targeting methods will be used to test the functional involvement of key nodes of the implicated circuits in stress-induced pituitary-adrenal hormone secretion and behavioral measures of anxiety. The results are expected to provide a systems level perspective on the role of the central CRF system in critical facets of the stress response, and a stringent test of the integrative capacities attributed to this system in stress adaptation.