Estrogen-mediated mechanisms of stress susceptibility

项目摘要 女性患与压力有关的情感障碍的可能性是男性的两倍，因此， 患心血管疾病的风险更大。该提案研究了雌激素（E）- 介导的神经机制，我们认为是在中央杏仁核（CeA）启动，以促进先天性 应激易受负效价和过度的心脏交感神经激活的影响。 拟议的一系列研究依赖于使用证人压力范式，即男性或女性 啮齿动物位于一个受保护的地区占主导地位的居民的笼子里，并见证了社会冲突之间 和一个体型较小的男性入侵者在应激暴露后，卵巢完整的雌性 激素，或切除卵巢与E替代（OVX+E）表现出负价（降低蔗糖 偏好，增加埋藏）和夸大的心脏交感神经水平（静息血压升高） 而OVX+溶媒替代（OVX+V）和完整雄性动物具有弹性，使该模型成为研究的理想模型 雌激素在增加压力敏感性中的作用。目标1扩展了初步数据， 卵巢激素，特别是E，加剧应激敏感性的假说。这些研究将确定 性别差异和雌激素对应激相关病理的行为和交感神经指标的影响。目的 2利用直接CeA内施用E受体（ER）激动剂（DPN）或拮抗剂（PHTPP）， 分别激活或阻断CeA中的ER。我们假设抑制这个大脑区域的ER 将增强先天易感（完整循环）和诱导易感（OVX+E）的应激弹性 女性群体，而激活受体将促进脆弱性的诱导弹性组（OVX）。一 已知E的作用是其增加应激相关神经肽促肾上腺皮质激素释放因子（CRF）的能力， 一种在CeA中含量丰富的肽，能够诱导增强的行为和交感恐惧 应答我们的数据表明，完整的女性表现出增加CRF的CeA，但只有当他们有一个 压力暴露史因此，目标2也将确定这些ER治疗是否影响CRF表达， 的CEA。最后，Aim 3将使用病毒介导的基因转移来降低CeA中的CRF水平，以确定 是否E的易感性增强作用依赖于CRF。此外，在体内使用 微透析，目标3中的研究将确定CeA中CRF增加是否对主要的 应激敏感靶点为蓝斑（LC）。将在LC中测量CRF释放和神经元活性 并将确定完整雌性动物是否在LC中表现出CRF释放增加，以及这是否 转化为更高的活性。在CeA中敲低shRNA CRF影响LC活性和CRF的能力 释放也将被评估。总之，这些研究将为靶向机制提供证据， 增加女性对情感障碍和共病心功能障碍的易感性。这些研究 提出了一种新的和“可翻译”的途径，通过这种途径E可以调节女性先天的压力脆弱性。

Project Summary Women are twice as likely as men to suffer from stress-related affective disorders, and as a result, are also at a greater risk of developing comorbid cardiovascular disease. This proposal investigates the estrogen (E)- mediated neural mechanisms that we suggest are initiated in the central amygdala (CeA) to promote innate stress vulnerability to both the emergence of negative valence and exaggerated cardiac sympathetic activation. The proposed series of studies relies on the use of a witness stress paradigm whereby a male or female rodent is located in a protected region of a dominant resident's cage and witnesses a social conflict between the resident and a smaller male intruder. Following stress exposure, females with either intact ovarian hormones, or ovariectomized with E replacement (OVX+E) exhibit negative valence (decreased sucrose preference, increased burying) and exaggerated cardiac sympathetic levels (elevated resting blood pressure) while OVX with vehicle replacement (OVX+V) and intact males are resilient, making this model ideal to study the role of estrogen on increased stress susceptibility. Aim 1 expands upon preliminary data that support the hypothesis that ovarian hormones, in particular E, exacerbate stress susceptibility. These studies will identify sex differences and estrogenic effects on behavioral and sympathetic indices of stress-related pathology. Aim 2 utilizes direct intra-CeA administration of an E receptor (ER) agonist (DPN) or antagonist (PHTPP), to activate or block, respectively, the ERs in the CeA. We hypothesize that inhibiting the ER in this brain region will enhance stress resiliency in the innate susceptible (intact-cycling) and induced susceptible (OVX+E) female groups, while activating the receptor will promote vulnerability in the induced resilient group (OVX). One known effect of E is its ability to increase the stress-related neuropeptide corticotropin-releasing factor (CRF), a peptide that is abundant in the CeA and is capable of inducing enhanced behavioral and sympathetic fear responses. Our data indicate that intact females exhibit increased CRF in the CeA, but only if they have a history of stress exposure. Therefore, Aim 2 will also identify if these ER treatments affect CRF expression in the CeA. Finally, Aim 3 will use virus-mediated gene transfer to reduce CRF levels in the CeA to determine whether the susceptibility-enhancing effects of the E are dependent upon CRF. Moreover, using in vivo microdialysis, studies in Aim 3 will identify whether increased CRF in the CeA has consequences on the major stress sensitive target the locus coeruleus (LC). CRF release and neuronal activity will be measured in the LC during stress/control and will identify if intact females exhibit increased CRF release in the LC and whether this translates to elevated activity. The ability of shRNA CRF knockdown in the CeA to affect LC activity and CRF release will also be assessed. Together, these studies will provide evidence of a targeted mechanism increasing susceptibility to affective disorders and comorbid cardiac dysfunction in females. These studies propose a novel and “translatable” pathway by which E may regulate innate stress vulnerability in women.