Neurobiology of Anxiety and Panic Disorders

描述（由申请人提供）：惊恐障碍是一种以显著残疾为特征的严重焦虑障碍。GABA抑制在下丘脑背内侧/皮层周围（DMH/PeF）区域长期中断的大鼠，表现出高度的焦虑和恐慌样反应，定义为心率（HR），平均动脉压（BP），呼吸频率（RR）和焦虑（通过社会互动（SI）测试测量）增加，暴露于阈下提示，如0.5 M乳酸钠和7.5%二氧化碳，已知会引起惊恐障碍受试者的惊恐发作。在上一个资助期内，我们广泛地描述了乳酸刺激的传入途径，展示了DMH内的一些调节机制，并确定了DMH的传出目标，这些目标与恐慌反应有关。这项竞争性更新（MH 52619）的目标是通过药理学、功能神经解剖学和分子研究进一步阐明参与恐慌反应不同组成部分的通路和神经递质。这项工作的总体假设是，大鼠DMH/PeF区域GABA抑制的破坏诱导了一种“恐慌倾向”状态，这是一组选择的谷氨酸/肽能投射神经元的病理激活的结果，最突出的是orexin/dynorphin a （ORX/DYN）阳性细胞。这导致DMH对一些传出靶标的异常刺激。在此资助期内，我们将研究激活终纹床核（BNST）导致焦虑样反应的途径，以及特定脑干投射靶点（如孤束核（NTS））在这些恐慌易感大鼠中引起副交感神经抑制和交感神经通路激活以增加HR和BP的途径。我们将用神经元免疫组化研究的实验来检验这些假设；全身注射ORX和其他肽受体拮抗剂；DMH/PeF中ORX神经元的靶向损伤；RTPCR检测proorx前（ppORX）、proDynorphin （pDYN）等肽mRNA表达变化；以及在DMH内用siRNA敲低急性ppORX和/或pDYN基因。我们将通过注射药物、使用siRNA进行基因沉默以及神经解剖学技术来研究传出部位。最后，我们将研究GAD-67/65基因沉默在DMH/PeF区域对局域GABA神经元和外源GABA神经元的作用。

DESCRIPTION (provided by applicant): Panic disorder is a severe anxiety disorders characterized by significant disability. Rats in which GABA inhibition is chronically disrupted in the dorsomedial hypothalamus/perifornical (DMH/PeF) region, exhibit heightened anxiety and panic-like responses, defined as increases in heart rate (HR), mean arterial pressure (BP), respiratory rate (RR), and anxiety as measured by the social interaction (SI) test, following exposure to subthreshold cues such as 0.5 M sodium lactate and 7.5% CO2, agents known to provoke panic attacks in subjects suffering from panic disorder. During the last funding period, we have extensively characterized the afferent pathways for the lactate stimulus, demonstrated some of the regulatory mechanisms within the DMH, and identified the efferent targets of the DMH that are implicated in the panic-like response. The goal of this competitive renewal (MH 52619) is to further elucidate the pathways and neurotransmitters involved in the different components of panic response using pharmacological, functional neuroanatomical, and molecular studies. Overall Hypothesis of the work is that disruption of GABA inhibition in the DMH/PeF region of rats induces a 'panic-prone' state, as a result of pathological activation of a select group of glutamate/peptidergic projection neurons, most prominently orexin/dynorphin A (ORX/DYN) positive cells. This results in aberrant stimulation of a number of efferent targets from the DMH. During this funding period, we will study the pathways involved in activating the bed nucleus of the stria terminalis (BNST) to result in anxiety-like responses and specific brain stem projection targets such as the nucleus tractus solitarius (NTS) in causing inhibition of parasympathetic and activation of sympathetic pathways to increase HR and BP following lactate infusions in these panic-prone rats. We will test these hypotheses with experiments using neuronal immunohistochemical studies; systemic injections of ORX and other peptide receptor antagonists; targeted lesioning of the ORX neurons in the DMH/PeF; measuring the changes in pre-proORX (ppORX), proDynorphin (pDYN) and other peptide mRNA expressions using RTPCR; and acute ppORX and/or pDYN gene knockdown with siRNA, within the DMH. We will study the efferent sites with infusions of pharmacological agents, gene silencing using siRNA as well as neuroanatomical techniques. Finally, we will study the role of local versus extrinsic GABA neurons by GAD-67/65 gene silencing in the DMH/PeF region.