Estrogen-mediated mechanisms of stress susceptibility

项目摘要 女性患压力相关情感障碍的可能性是男性的两倍，因此也是 患心血管疾病的风险更大。这项提案研究雌激素(E)- 我们认为在中央杏仁核(CEA)启动的中介神经机制促进先天的 应激易受负价态的出现和心脏交感神经激活的夸大。 拟议的一系列研究依赖于证人应激范例的使用，即男性或女性 啮齿动物位于一只占主导地位的居民笼子的保护区内，目睹了 居民和一名较小的男性入侵者。应激暴露后，卵巢完好的雌性 激素，或卵巢切除加E替代(OVX+E)表现为负价(蔗糖减少 偏爱，更多的埋藏)和夸大的心脏交感神经水平(静息血压升高) 而带有车辆替换(OVX+V)的OVX和完好无损的雄性OVX具有弹性，使该模型成为研究的理想模型 雌激素在增加应激敏感性中的作用。目标1扩展了初步数据，这些数据支持 假设卵巢激素，特别是E，会加剧压力易感性。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指数的影响。目标 2利用CEA内直接注射E受体(ER)激动剂(DPN)或拮抗剂(PHTPP)，以 分别激活或阻止CEA中的ER。我们假设抑制这个脑区的内质网 将增强先天易感(完整循环)和诱导易感(OVX+E)的应激恢复能力 在女性群体中，当激活受体时，将促进诱导弹性群体(OVX)的脆弱性。一 已知的作用是E能够增加应激相关神经肽促肾上腺皮质激素释放因子(CRF)，a CEA中丰富的一种多肽，能够引起增强的行为和交感恐惧 回应。我们的数据表明，完整的女性在CEA中表现出更多的CRF，但只有当她们有一个 有压力暴露史。因此，AIM 2还将确定这些ER处理是否影响CRF在 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 E的易感性增强作用是否取决于CRF。此外，在体内使用 微透析，AIM 3中的研究将确定CEA中CRF增加是否对主要 应激敏感靶点为蓝斑(LC)。将在LC中测量CRF释放和神经元活动 在压力/控制期间，将确定完整的女性是否表现出LC中CRF释放的增加，以及这是否 转化为更活跃的活动。CEA中shRNA CRF基因敲除对LC活性和CRF的影响 还将对释放进行评估。总之，这些研究将提供有针对性的机制的证据。 女性对情感障碍和共病心功能不全的易感性增加。这些研究 提出一种新的、“可翻译的”途径，通过该途径，E可以调节女性的先天应激脆弱性。

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.