Investigation of non-canonical opioid signaling in the prefrontal cortex of alcohol-dependent rats

项目摘要 目前酒精使用障碍（AUD）的治疗在减少重度酒精方面取得了一定的成功 但由于治疗依从性问题而受到损害。在临床上，阿片受体药剂学 通常与认知行为疗法相结合，以改善长期禁欲。这些发现表明 内源性阿片信号传导与认知因素在治疗AUD中的重要关系; 然而，治疗的失误可以迅速恢复饮酒，突出了我们在知识上的差距。 了解这些机制如何影响长期滥用。因此，酒精消费 刺激内源性阿片类物质的释放，包括与μ型阿片受体（莫尔）结合的脑啡肽 常见于大脑边缘区域对莫尔信号的操纵改变了奖赏特性 酒精，激动剂促进奖励和消费，拮抗剂阻断这些反应。的 作为动机和认知基础的阿片能反应之间的共同关系尚未得到很好的理解 但是为解决可能导致酒精相关敏感性的复杂病理提供了焦点。在 就这一点而言，MORs存在于调节认知功能的额叶皮质区域，如内侧皮层， 前额叶皮层（mPFC）。我们实验室的临床前研究表明， 降低mPFC中莫尔的磷酸化，并增加神经肽前体的表达， 脑啡肽原（PENK）。这种变化模式与临床观察到的莫尔脱敏重叠， AUD患者。研究结果表明，依赖可能会失调阿片类药物在mPFC的信号， 尽管这些条件对内源性配体的表面变化的影响程度尚不清楚。更好的 考虑到对阿片类拮抗剂的坚持会随着长期禁欲而减少， 并且可能被小阿片肽加工过程中的分子中间体破坏。在这里，我们将 探索中心假设，即mPFC中的非经典PENK信号传导在 在禁欲期间认知功能失调为了实现这一目标，基于发现和定量的质量 光谱分析方法将与体内微透析相结合，以广泛捕获PENK介导的 信号在酒精依赖大鼠经历禁欲（目的1）。然后，我们将探讨功能相关性 在认知灵活性的操作模型中的非典型PENK信号传导，并进一步确定是否 mPFC莫尔调节依赖性中的类似功能障碍（目的2）。预计结果将提供 深入了解可药用靶点，这些靶点超出了传统的阿片样物质信号传导过程， 探索非经典PENK信号在驱动脆弱性中的作用的机制研究基金会 成瘾行为

Project Abstract Current treatments of Alcohol Use Disorder (AUD) have shown moderate success in reducing heavy alcohol drinking but are marred with the problem of treatment adherence. In the clinic, opiate receptor pharmaceutics are often combined with cognitive behavioral therapies to improve long-term abstinence. These findings suggest an important relation between endogenous opioid signaling and cognitive factors in the treatment of AUD; however, lapses in treatment can quickly reinstate alcohol drinking, highlighting a knowledge gap in our understanding of how these mechanisms may influence long-term misuse. In this regard, alcohol consumption stimulates the release of endogenous opioids, including enkephalins that bind to mu-type opioid receptors (MOR) commonly found in limbic areas of the brain. The manipulation of MOR signaling alters the rewarding properties of alcohol, with agonists facilitating reward and consumption, and antagonists blocking these responses. The shared relation between opioidergic responses that underlie motivation and cognition are not well understood but present a focal point for addressing complex pathologies that may underlie alcohol-related sensitivities. In this regard, MORs are found in frontal cortical regions that modulate cognitive function, such as the medial prefrontal cortex (mPFC). Preclinical studies in our laboratory demonstrate that alcohol dependence in rats decreases the phosphorylation of MOR in the mPFC, and increases expression of the neuropeptide precursor, proenkephalin (PENK). This pattern of changes overlaps with clinical observations of MOR desensitization in AUD patients. The findings suggest that dependence may dysregulate opioidergic signaling in the mPFC, although the extent to which such conditions surmise changes in the endogenous ligands is unclear. A better understanding is warranted given that adherence to opiate antagonists diminishes over protracted abstinence and may be undermined by molecular intermediates in the processing of small-opioid peptides. Here, we will explore the central hypothesis that non-canonical PENK signaling in the mPFC plays a pivotal role in dysregulating cognitive function during abstinence. Towards this goal, discovery-based and quantitative mass spectrometry approaches will be combined with in vivo microdialysis to broadly capture PENK-mediated signaling in alcohol-dependent rats undergoing abstinence (Aim 1). We will then explore the functional relevance of non-canonical PENK signaling in an operant model of cognitive flexibility, and further determine whether similar dysfunctions in dependence are modulated by mPFC MOR (Aim 2). The results are expected to provide insight into druggable targets that extend beyond conventional opioidergic signaling processes and will lay the foundation for mechanistic studies exploring the role of non-canonical PENK signaling in driving vulnerability to addiction behavior.