Impact of fentanyl dependence on a parabrachio-amygdalar opioid circuit

项目概要/摘要 阿片类药物使用障碍仍然是一个可怕的公共卫生问题，但阿片类药物激动剂，如芬太尼，仍然是第一， 线治疗几种疼痛条件。在娱乐性使用环境中， 管理可以产生身体依赖性和疼痛阈值和耐受性的反常降低， 这增加了患者对阿片类药物的依赖，并增加了转变为阿片类药物使用障碍的可能性。 持续刺激抑制性μ-阿片受体（莫尔），镇痛剂的主要介质， 阿片受体激动剂的奖励作用，诱导反适应性兴奋过程和过度兴奋， 表达MOR的神经元。发现新的治疗方法，利用阿片类药物的好处，但减轻厌恶 和长期使用阿片类药物的危及生命的副作用，关键是要确定特定的细胞类型， 大脑中的神经回路对阿片类药物诱导的细胞适应不良敏感， 依赖和OIH。MORs在整个上行疼痛通路中密集表达，包括在 脑桥臂旁核（PBNMOR）。PBNMOR神经元投射到中枢神经系统的被膜区。 杏仁核（CeC），其本身含有表达蛋白激酶C-δ的原伤害感受神经元群体 （CeCPKCδ）PBNMOR®CeC通路的激活降低疼痛耐受性并增加厌恶相关性 反应，但它在驱动OIH和戒断中的作用，特别是CeCPKCδ神经元的贡献， 没有被调查。该提案的目标是确定芬太尼依赖对神经系统的影响。 PBNMOR®CeCPKCδ通路中的活性以及这种活性是否驱动戒断和OIH相关行为。 目的1将研究芬太尼依赖对PBNMOR®CeC投射的影响及其在驱动 通过使用体内群体钙成像和化学遗传学操作的OIH和戒断行为 在伤害性测定和戒断期间。目标2将在以下过程中成像和操作CeCPKCδ群体： 行为，以确定其贡献OIH和退出。这些目标的成功实现将奠定 为未来阿片类药物依赖的病理生理学研究奠定基础。理想情况下，这项工作的成果 将提出减少特定细胞类型内依赖机制的新的治疗途径。女士 Wooldridge将接受化学遗传学、体内钙成像及其分析、病毒介导的 基因靶向，严格的实验设计和统计。增加这一培训将有助于 申请人当前和未来的研究目标，使她能够对基础神经科学产生持续的影响 作为一名独立的学术研究人员，在未来的职业生涯中进行研究。

Project Summary/Abstract Opioid Use Disorder remains a dire public health problem, but opioid agonists such as fentanyl remain a first- line therapy for several pain conditions. As in recreational use settings, prolonged use of opioid agonists in pain management can produce physical dependence and a paradoxical decrease in pain thresholds and tolerance, which increase patients’ reliance on opioids and increase the likelihood of transitioning to Opioid Use Disorder. Continual stimulation of the inhibitory µ-opioid receptor (MOR), the primary mediator of the analgesic and rewarding effects of opioid agonists, induces counter-adaptive excitatory processes and hyperexcitability in MOR-expressing neurons. To discover new treatments that leverage the benefits of opioids but mitigate aversive and life-threatening side effects of prolonged opioid use, it is critical to determine the specific cell-types and neural circuits in the brain that are susceptible to the opioid-induced cellular maladaptations that underlie dependence and OIH. MORs are densely expressed throughout ascending pain pathways, including in the parabrachial nucleus of the pons (PBNMOR). PBNMOR neurons project to the capsular region of the central amygdala (CeC), which itself contains a pronociceptive population of neurons expressing Protein Kinase C-δ (CeCPKCδ) Activation of the PBNMOR®CeC pathway decreases pain tolerance and increases aversion-related responses, but its role in driving OIH and withdrawal, and the contribution of CeCPKCδ neurons in particular, has not been investigated. The goal of the proposal is to determine the impact of fentanyl dependence on the neural activity in the PBNMOR®CeCPKCδ pathway and whether such activity drives withdrawal and OIH-related behaviors. Aim 1 will investigate the effects of fentanyl dependence on PBNMOR®CeC projections and their role in driving OIH and withdrawal behavior by using in vivo population calcium imaging and chemogenetic manipulations during nociceptive assays and withdrawal. Aim 2 will image and manipulate the CeCPKCδ population during behavior to determine its contribution to OIH and withdrawal. Successful completion of these Aims will lay the foundation for future investigations of the pathophysiology of opioid dependence. Ideally, results from this work will suggest novel therapeutic avenues for reducing dependence mechanisms within specific cell-types. Ms. Wooldridge will receive expert training in chemogenetics, in vivo calcium imaging and its analysis, viral-mediated genetic targeting, and rigorous experimental design and statistics. The addition of this training will facilitate the applicant’s current and future research goals and enable her to have continual impact on basic neuroscience research throughout a future career as an independent academic researcher.