Phenotypic and Functional Determination of Central Extended Amygdala Cell Groups

描述（由申请人提供）：该提案侧重于中央延伸杏仁核的一部分的大脑区域：杏仁核中央核（CEA）。CEA参与对恐惧、压力和焦虑的许多反应，并包含不同的细胞群。然而，尚不清楚细胞群是否具有不同的功能，并且目前不可能利用可用的工具在体内确定这一点。该提议旨在测试使用神经肽B和W 1型受体（NPBW 1）作为靶标在CEA中形成特定神经元群体的选择性神经毒性损伤的可行性。该受体非常离散地表达，特别是在外侧CEA中，但不在周围区域中。此外，该受体表达在含有促肾上腺皮质激素释放激素（CRH）和强啡肽的外侧CEA的细胞上，但不表达在含有脑啡肽的细胞上，或在内侧CEA的细胞上，内侧CEA是杏仁输出神经元的主要来源。该受体的选择性配体（神经肽W-30）将与皂草素（由Advanced Targeting Systems）定制缀合。目的1是发展一种有效的、选择性的CEA神经毒性损伤。配体将与NPBW 1受体结合，当内化时将释放皂草素进入细胞，导致细胞死亡。这种方法的效用已被证明用于其他受体系统，包括选择性靶向杏仁核的嵌入核的细胞，使用μ阿片受体作为靶标。NPBW 1受体定位的特异性表明，这种损伤方法将选择性地破坏含有CRH和强啡肽的细胞，但保留外侧CEA中含有脑啡肽的细胞和内侧CEA内的杏仁输出细胞，这些细胞被认为对调节几种恐惧和焦虑反应（例如恐惧增强的惊吓反应）至关重要。目的2：在成年雄性大鼠中，评估中央延伸杏仁核CRH/强啡肽细胞的潜在功能。这些实验将首先评估CEA的这种神经毒性损伤对A）高架十字迷宫和防御性退缩范例中的基础焦虑样行为和B）恐惧增强的听觉惊吓反射的影响。希望开发一种选择性靶向CEA特定群体的工具将有助于定义其功能，最初强调细胞在恐惧和焦虑样反应中可能发挥的作用。希望随着时间的推移，这项工作将最终导致中央延伸杏仁核中几种不同细胞类型的神经毒性病变的发展，包括终纹的床核，并且总体上，这将导致更好地理解与许多恐惧和焦虑相关疾病的发展和恶化相关的负面情绪的处理。该提案旨在选择性地去除大脑中被认为与压力，恐惧和/或焦虑反应有关的特定神经元群体。希望有选择地针对特定人群（而不是目前可用的更全球化的方法）将更好地了解大脑如何处理这些负面情绪。这反过来将有助于设计焦虑和恐惧相关疾病的治疗策略。

DESCRIPTION (provided by applicant): This proposal focuses on a brain area that is part of the central extended amygdala: the central nucleus of the amygdala (CEA). The CEA is involved in a number of responses to fear, stress and anxiety and contains distinct cell populations. However, it is not known whether the cell populations have distinct functions, and it is currently impossible to ascertain this in vivo with the tools available. This proposal aims to test the feasibility of developing a selective neurotoxic lesion of a specific neuronal population in the CEA using the neuropeptide B and W type 1 receptor (NPBW1) as a target. This receptor is very discretely expressed, specifically in the lateral CEA, but not in the surrounding areas. Furthermore, this receptor is expressed on cells of the lateral CEA that contain corticotropin releasing hormone (CRH) and dynorphin, but is not expressed on cells that contain enkephalin, or on cells of the medial CEA, a major source of amygdaloid output neurons. A selective ligand for this receptor (neuropeptide W-30) will be custom conjugated with saporin (by Advanced Targeting Systems). Aim 1 focuses on the development of an effective and selective neurotoxic lesion of the CEA. The ligand will bind to the NPBW1 receptor and when internalized will release saporin into the cell, causing the death of the cell. The utility of this approach has been shown for other receptor systems, including selective targeting of cells of the intercalated nuclei of the amygdala, using the mu opioid receptor as a target. The specificity of the localization of the NPBW1 receptor suggests that this lesioning method will selectively destroy cells containing CRH and dynorphin, but spare both enkephalin containing cells in the lateral CEA, and amygdaloid output cells within the medial CEA that are thought to be critical for modulation of several fear and anxiety responses (e.g. fear potentiated startle response). In Aim 2, the potential functions of CRH/dynorphin cells of the central extended amygdala will be assessed in adult male rats. These experiments will initially evaluate the effects of this neurotoxic lesion of the CEA on A) basal anxiety-like behaviors in the elevated plus maze and defensive withdrawal paradigm, and B) fear-potentiated acoustic startle reflexes. It is hoped that the development of a tool to selectively target a specific population of the CEA will help to define its functions, with an initial emphasis on the roles that the cells may play in fear and anxiety-like responses. It is hoped that with time, this work will ultimately lead to the development of neurotoxic lesions of several distinct cell types in the central extended amygdala, including the bed nucleus of the stria terminalis, and collectively, this will lead to a better understanding of the processing of negative emotions that are associated with the development and exacerbation of many fear and anxiety-related disorders. This proposal aims to selectively remove a specific neuronal population in the brain that is thought to be involved in stress, fear and/or anxiety responses. It is hoped that selectively targeting a specific population (rather than the more global approach currently available) will lead to a better understanding of how the brain processes these negative emotions. This in turn will be helpful in the design of treatment strategies for anxiety and fear-related disorders.