Role of Dynorphin and Kappa Opioid Receptors in Stress Effects on Ethanol Dependence-Related Escalated Drinking

描述(由申请人提供)：酒精依赖是一个广泛的公共卫生问题，可供选择的治疗方法有限。这种慢性复发性疾病的特点是在戒酒后恢复大量使用，并可以使用公认的慢性间歇性乙醇(CIE)暴露程序在啮齿动物身上建立模型。虽然众所周知，压力会促进饮酒，特别是会引发复发，但人们对压力暴露对过渡到与依赖相关的过度饮酒水平的影响知之甚少。我们的实验室表明，强迫游泳应激暴露会加速CIE酒精依赖模型中过度饮酒的出现速度，并增加依赖但不依赖的受试者的饮酒增加幅度。强啡肽/kappa阿片受体(KOR)系统参与调节与依赖相关的应激反应和酒精消耗。因此，有理由认为强啡肽/KOR系统可能在这种与CIE饮酒模型的应激相互作用中发挥作用。本研究旨在探讨强啡肽/KOR活性在乙醇依赖小鼠CIE模型中调节应激暴露促进和增强饮酒升级能力中的作用。拟议的研究将采用系统药理学和特定部位的药物合成方法。对于目标1，我将使用我们的强迫游泳应激(FSS)-CIE饮酒范式来(1)评估新型、短效、选择性KOR拮抗剂FP3FBZ的应用是否减弱CIE诱导的饮酒加剧的应激促进作用，以及(2)确定与非依赖对照组相比，全身应用KOR激动剂U50,488是否可以替代和模仿FSS暴露在增加CIE暴露小鼠的酒精饮酒量方面的效果。为了实现目标2，我将在同一FSS-CIE饮酒模型中使用设计者受体技术(病毒注射依赖CRE的DREADDS)和前强啡肽-IRES-Cre转基因小鼠，以(1)确定与非依赖对照相比，杏仁中央核中“沉默”的强啡肽神经元(通过激活抑制性DREADD)是否可以阻止CIE诱导的饮酒加剧的应激促进作用，(2)评估与非依赖对照相比，杏仁中央核强啡肽神经元的激活(通过兴奋性DREADD)是否可以替代和模仿应激暴露在增加酒精摄入量方面的效果。这个项目的结果将促进我们对压力能力的神经机制的理解，以促进向 过量饮酒与依赖有关，并表明KOR系统有可能成为酒精依赖治疗战略的治疗目标。

DESCRIPTION (provided by applicant): Alcohol dependence is a widespread public health concern with limited treatment options available. This chronic, relapsing disorder is characterized by periods of abstinence followed by a return to heavy use and can be modeled in rodents using a well-established chronic intermittent ethanol (CIE) exposure procedure. While stress is known to promote alcohol consumption and, in particular, trigger relapse, the influence of stress exposure on transition to excessive levels of drinking associated with dependence is less well understood. Our lab has shown that forced swim stress exposure accelerates the rate at which excessive drinking emerges in the CIE model of ethanol dependence and enhances the magnitude of escalated consumption in dependent but not nondependent subjects. The dynorphin/kappa opioid receptor (KOR) system is implicated in modulating both stress responses and ethanol consumption associated with dependence. Thus, it is plausible to suggest that the dynorphin/KOR system may play a role in this stress interaction with the CIE-drinking model. This research project is focused on examining the role of dynorphin/KOR activity in mediating the ability of stress exposure to facilitate and enhance escalation of drinkig in the mouse CIE model of ethanol dependence. The proposed studies will employ both systemic pharmacological and site-specific pharmacosynthetic approaches. For Aim 1, I will use our forced swim stress (FSS)-CIE-drinking paradigm to (1) assess whether administration of the novel, short-acting, selective KOR antagonist FP3FBZ attenuates stress facilitation of CIE-induced escalated drinking and (2) determine whether systemic administration of the KOR agonist U50,488 can substitute for and mimic the effects of FSS exposure in increasing ethanol drinking in CIE- exposed mice compared to nondependent controls. For Aim 2, I will use designer receptor technology (viral injection of Cre-dependent DREADDs) along with prodynorphin-IRES-Cre transgenic mice in the same FSS- CIE-drinking model to (1) determine whether 'silencing' dynorphin neurons (via activation of inhibitory DREADDs) in the central amygdala blocks stress facilitation of CIE-induced escalated drinking and (2) assess whether activation of dynorphin neurons (via excitatory DREADDs) in the central amygdala can substitute for and mimic the effects of stress exposure in enhancing ethanol intake in CIE-exposed mice compared to nondependent controls. Results from this project will advance our understanding of the neural mechanisms underlying the ability of stress to facilitate transition to excessive ethanol drinking associated with dependence, as well as characterize the potential for the KOR system to serve as a therapeutic target for treatment strategies for alcohol dependence.