Stimulant-induced excitatory and inhibitory dopamine receptor signaling and trafficking

项目摘要 多巴胺系统在物质使用障碍的发病机制中起着重要作用。兴奋剂使用 和滥用导致几种多巴胺能改变，这些改变导致与 成瘾的形成。一次急性接触兴奋剂可在早期触发受体内化 突触对高浓度多巴胺的适应机制。这些机制已经被证明能够影响 神经成像结果，特别是正电子发射断层扫描(PET)，它揭示了自相矛盾的 兴奋剂诱导的多巴胺释放后，多巴胺D2/D3受体的可获得性长期下降。迄今为止，我们 对多巴胺受体内化和恢复的时间线仍有有限的了解 药物暴露以及这些适应机制如何影响兴奋性D1和D2的全脑信号 抑制性D2型受体。这项研究旨在通过描述两个班级如何 兴奋剂药物(苯丙胺和哌醋甲酯)调节多巴胺受体亚型信号转导和 随着时间的推移，受体的交易。使用最先进的同步PET和功能磁共振 非人灵长类动物的成像(FMRI)方法--苯丙胺诱导受体的时间尺度 将通过反复服用苯丙胺来实现内化和再循环。目标明确 多巴胺能阻断药物将与苯丙胺配对，以确定兴奋性之间的平衡 D1和抑制性D2受体的信号和运输随着时间的推移而被调制。重复的影响 然后将苯丙胺与哌醋甲酯进行比较，以评估不同水平的多巴胺激增。 以及这两种兴奋剂的不同作用机制。总体而言，这项研究将揭开大脑-- 反复接触兴奋剂引起的分子和功能的变化 在翻译动物模型中活体大脑中的多巴胺受体运输。结果将阐明这一角色 多巴胺D1型和D2型受体适应性的研究，从而提供了对神经生物学的重要见解 重复使用刺激性药物的机制与启动和最终预防药物有关 敏感化和成瘾。

Project Summary The dopamine system plays a major role in the pathogenesis of substance use disorders. Stimulant drug use and abuse lead to several dopaminergic alterations that contribute to the complex behavior associated with the formation of addiction. A single acute exposure to a stimulant drug can trigger receptor internalization as an early synaptic adaptation mechanism to high dopamine concentrations. These mechanisms have been shown to affect neuroimaging outcomes, specifically positron emission tomography (PET), which has revealed paradoxically long reductions in dopamine D2/D3 receptor availability after stimulant-induced dopamine release. To date, we still have a limited understanding of the timeline of dopamine receptor internalization and recovery with repeated drug exposure and how these adaptation mechanisms affect whole-brain signaling of both excitatory D1 and inhibitory D2-type receptors. This study aims to address this knowledge gap by characterizing how two classes of stimulant drugs (amphetamine and methylphenidate) modulate dopamine receptor subtype signaling and receptor trafficking over time. Using state-of-the-art simultaneous PET and functional magnetic resonance imaging (fMRI) methodology in non-human primates, the timescales of amphetamine-induced receptor internalization and recycling will be established using repeated amphetamine administrations. Targeted dopaminergic blocking drugs will be paired with amphetamine to determine how the balance between excitatory D1 and inhibitory D2 receptor signaling and trafficking is modulated over time. The effects of repeated amphetamine will then be compared to those of methylphenidate to assess varying levels of dopamine surges and differential mechanisms of action across these two stimulant drugs. Overall, this study will unravel brain- wide molecular and functional changes due to repeated stimulant drug exposure by imaging the timescales of dopamine receptor trafficking in the living brain in a translational animal model. The results will elucidate the role of dopamine D1 and D2-type receptor adaptations, thereby providing important insight into the neurobiological mechanisms involved in repeated stimulant drug use relevant for initiating and eventually preventing drug sensitization and addiction.