Role of OFQ/N in Regulating the Prolactin Response to Stress

描述（由申请人提供）：压力在生活中的某个时刻几乎影响着社会中的每个人，它对健康有重大的有害影响。它会导致许多疾病，包括心血管、免疫和生殖系统疾病，以及睡眠障碍、抑郁症和药物滥用。尽管如此，调节应激生理反应的神经内分泌机制仍然知之甚少，特别是催乳素分泌的调节和作用。这些研究的总体目标是了解应激时催乳素分泌的调节及其对下丘脑-垂体-肾上腺（HPA）轴应激反应的影响。主要假设是内源性阿片，孤啡肽/孤啡肽（OFQ/N），是一种重要的神经肽调节催乳素分泌在应激过程中。将使用OFQ/N敲除模型，因为它非常适合这些研究。首先，基因敲除小鼠对压力的反应与野生型小鼠不同;这对雄性和雌性都是如此。急性应激增加血浆催乳素水平在野生型，但不敲除男性。此外，OFQ/N敲除，但不是野生型女性继续响应反复的压力，这表明PRL反馈是不活跃时，OFQ/N是缺席。具体目标1和2将研究OFQ/N在调节这些性别差异方面的作用和作用机制。第二，基因敲除的产后女性没有高泌乳素血症，似乎没有增加的PRL-R mRNA在脉络丛的大脑，使他们从正常的产后女性有很大的不同。在具体目标3中，我们将利用这种差异来研究高泌乳素血症的OFQ/N调节中所涉及的作用和机制，以及催乳素在介导HPA轴对应激反应衰减中的作用和机制。将测量血浆皮质酮水平（应激激活的可靠指标）和血浆PRL水平。为了确定调节应激反应的机制，将测定结节漏斗多巴胺能神经元活性、垂体前叶催乳素含量、下丘脑脉络丛和室旁核（PVN）中的催乳素受体表达以及PVN中的CRH mRNA水平。将通过给予催乳素抗血清以阻断由催乳素水平升高介导的效应来证明作用的特异性。虽然对OFQ/N的神经内分泌作用知之甚少，但我们的研究表明OFQ/N在催乳素调节中起重要作用。这些研究将有助于阐明OFQ/N介导催乳素应激反应的机制和生理意义，以及催乳素对HPA轴激活的影响。了解调节压力反应的神经内分泌机制将有助于改善缓解压力和焦虑的治疗方法，从而对健康产生积极影响。压力在生活中的某个时刻影响着社会中的几乎每个人，并产生重大的有害影响。它导致许多病理学，包括但不限于心血管、免疫和生殖系统疾病，以及睡眠障碍、抑郁症和药物滥用。在工作生产率和医疗保健方面，社会的成本是惊人的。这些研究的重点是神经内分泌应激反应，特别是内源性阿片，孤啡肽/孤啡肽，一个所谓的抗焦虑，在催乳素调节的作用。催乳素在应激反应中至关重要，但其作用机制知之甚少。了解压力的神经内分泌调节将有助于改善缓解压力和焦虑的治疗方法，从而对健康产生积极影响。

DESCRIPTION (provided by applicant): Stress affects virtually everyone in society at some point in life and it has major deleterious effects on health. It contributes to numerous pathologies, including disorders in the cardiovascular, immune and reproductive systems, as well as sleep disorders, depression and substance abuse. In spite of this, the neuroendocrine mechanisms regulating the physiological responses to stress remain poorly understood, particularly the regulation and role of prolactin secretion. The overall goal of these studies is to understand the regulation of prolactin secretion during stress and its impact on the response of hypothalamic-pituitary adrenal (HPA) axis to stress. The major hypothesis is that the endogenous opiate, Orphanin FQ/Nociceptin (OFQ/N), is an important neuropeptide regulating prolactin secretion during stress. The OFQ/N knock out model will be used because it is ideally suited to these studies. First, knock out mice do not respond to stress in the same way as wild type mice; this is true for both males and females. Acute stress increased plasma prolactin levels in wild type, but not knock out males. Also, OFQ/N knock out, but not wild type females continued to respond to repeated stress, suggesting PRL feedback is not active when OFQ/N is absent. The role and mechanisms of action of OFQ/N in mediating these gender differences will be examined in Specific Aims 1 and 2. Second, knock out post-partum females are not hyperprolactinemic and do not seem to have increased PRL-R mRNA in the choroid plexus of the brain, making them much different from normal post-partum females. In Specific Aim 3, we will take advantage of this difference to examine the role and mechanisms involved in OFQ/N regulation of hyperprolactinemia and prolactin's role and mechanisms of action in mediating attenuation of the HPA axis response to stress. Plasma corticosterone levels, a reliable indicator of stress activation, and plasma PRL levels will be measured. To determine the mechanisms regulating the stress response, tuberoinfundibular dopaminergic neuronal activity, anterior pituitary prolactin content, prolactin receptor expression in the choroid plexus and paraventricular nucleus (PVN) of the hypothalamus and CRH mRNA levels in the PVN will be determined. Specificity of action will be demonstrated by administering prolactin antiserum to block effects mediated by increased prolactin levels. Although little is known about the neuroendocrine effects of OFQ/N, our studies indicate that OFQ/N plays an important role in prolactin regulation. These studies will determine the mechanisms and physiological significance of OFQ/N in mediating the prolactin response to stress and the effects of prolactin on HPA axis activation. Understanding the neuroendocrine mechanisms regulating the stress response will lead to improved treatments for alleviating stress and anxiety, and hence, have a positive impact on health. Stress affects virtually everyone in society at some point in life, and has major deleterious effects. It contributes to numerous pathologies, including, but not limited to, disorders in the cardiovascular, immune and reproductive systems, as well as sleep disorders, depression and substance abuse. The cost to society in terms of job productivity and health care is staggering. The focus of these studies is on the neuroendocrine response to stress, particularly on the role of the endogenous opiate, Orphanin FQ/Nociceptin, a purported anxiolytic, in prolactin regulation. Prolactin is critically important in the stress response, but its mechanisms of action are poorly understood. Understanding the neuroendocrine regulation of stress will lead to improved treatments to alleviate stress and anxiety, and hence, have a positive impact on health.