Mechanisms of Emotional Stress Effects on Hypothalamus

描述（由申请人提供）：下丘脑室旁核（PVH）是组织对情绪应激的适应性反应的关键结构，主要是由于它在激活垂体-肾上腺（糖皮质激素）反应中不可或缺的作用。提出了四组实验来阐明介导PVH对急性情绪应激反应的电路和细胞机制，以及这些如何通过反复应激暴露来修改。首先，立即早期基因引导消融策略将验证PVH对急性情绪应激（足部休克）的反应是通过通过丘脑进入前脑的脊髓伤害感受通路介导的假设。将使用经典条件反射范式来确定急性足震PVH募集的传入介导是否以及如何转移到服务于不同感觉模态的通路上。其次，我们将验证儿茶酚胺输入通过加强由其他系统发起的主要驱动来调节PVH对急性情绪压力的反应的假设。局部抑制PVH输入的功能组织将通过评估应激和甾体激素对gaba能传入源的影响来表征。我们将尝试建立PVH选择性gaba能去神经支配的方法，以便直接评估这种神经支配的作用。免疫毒素消融将用于[寻求]初步迹象，表明食欲素肽系统参与了情绪应激对PVH的影响。第三，将对PVH微解剖亚区进行转录分析，以验证PVH对反复情绪应激反应的习惯化涉及内在机制的假设。控制糖皮质激素水平的动物将被用来确定激素如何以及在哪里与传入回路相互作用以影响习惯化。最后，为了开始将神经回路与细胞机制联系起来，将使用药理学方法来评估肾上腺素能神经传递在急性应激对基因转录的影响，这些基因编码肽相互作用以控制垂体-肾上腺输出。慢病毒载体介导的基因转移将用于评估关键转录因子环AMP反应元件结合蛋白在这种情况下的作用。垂体-肾上腺系统的糖皮质激素产物有助于应对急性紧急情况，但在慢性情绪压力中看到的激素水平持续升高，是多种系统，精神甚至神经退行性疾病的促成或加剧因素。对这些适应的回路和机制的更全面的基本理解将促进对压力相关疾病的更有效的管理。

DESCRIPTION (provided by applicant): The paraventricular nucleus of the hypothalamus (PVH) is a pivotal structure in organizing adaptive responses to emotional stress, largely by virtue of its indispensable role in activating pituitary-adrenal (glucocorticoid) responses. Four sets of experiments are proposed to clarify the circuits and cellular mechanisms that mediate PVH responses to acute emotional stress, and how these come to be modified by repeated stress exposure. First, an immediate-early gene-guided ablation strategy will test the hypothesis that PVH responses to an acute emotional stress, footshock, are mediated via spinal nociceptive pathways that access the forebrain via the thalamus. A classical conditioning paradigm will be used to determine whether and how the afferent mediation of PVH recruitment by acute footshock may be transferred to pathways subserving a different sensory modality. Second, we will test the hypothesis that catecholamine inputs modulate PVH responses to acute emotional stress by reinforcing a primary drive initiated by other systems. The functional organization of local inhibitory inputs to PVH will be characterized by assessing stress and steroidal influences on identified sources of GABAergic afferents. We will attempt to establish a method for selective GABAergic denervation of PVH, to allow the role of this innervation to be assessed directly. Immunotoxin ablations will be used to [pursue] preliminary indications of an involvement of the orexin peptide system in emotional stress effects on PVH. Third, transcriptional profiling of microdissected PVH subregions will be carried out to test the hypothesis that intrinsic mechanisms are involved in habituation of PVH response to repeated emotional stress. Animals with controlled glucocorticoid levels will be used to determine how and where the hormone interacts with afferent circuitry to effect habituation. Finally, to begin to relate circuitry to cellular mechanisms, pharmacologic methods will be used to assess the role of adrenergic neurotransmission in acute stress effects on the transcription of genes encoding peptides that interact to govern pituitary-adrenal output. Lentiviral vector-mediated gene transfer will be used to evaluate the role in this context of a key transcription factor, the cyclic AMP response element-binding protein. Glucocorticoid products of the pituitary-adrenal system facilitate coping with acute emergencies, but sustained elevations in hormone levels, as seen in chronic emotional stress, is a contributing or exacerbating factor in diverse systemic, psychiatric and even neurodegenerative disorders. A fuller basic understanding of circuits and mechanisms underlying these adaptations will promote more effective management of stress related disease.