Glutamatergic plasticity that drives cannabinoid withdrawal and craving

项目总结/摘要 大麻是美国最常使用的非法药物。使用大麻的开始通常发生在 在青春期，这是一个脆弱的时期，在神经生物学发展。由于不确定性 围绕青少年接触大麻的长期后果，人们越来越担心， 放松法律的限制将导致青少年使用的增加。大约30%的用户开发 大麻使用障碍（CUD），近一半的常规大麻使用者发展大麻戒断 综合征，其特征是消极的情感症状和可能导致复发的渴望。期间 禁欲渴望可能会随着时间的推移而增加或“孵化”，导致一段时间内对 对药物相关线索的反应。戒断期间的戒断症状具有临床意义 因为它们可能会影响减少大麻使用的努力，促进其他滥用物质的使用， 对治疗结果产生不利影响。目前尚无获批的药物治疗CUD。的 该提案的主要目标是确定青少年长期使用大麻素如何影响 延髓核（NAc）中的神经递质传递和可塑性，以及这些神经递质的作用 对后来复发性行为和渴望的适应。我们的中心假设是大麻素自身- 给药和停药引起NAc中谷氨酸传递和突触连接的变化 这会促进消极的情感过程并最终引发复发。为了验证这一假设，我们将使用 行为，整体免疫组织化学和光片显微镜，光遗传学辅助神经生理学， 和化学遗传学操作技术，以评估通路特异性血管生成的参与， 神经可塑性在大麻寻求中的作用我们将使用青少年静脉注射D9-四氢大麻酚的模型， (THC)自我给药和停药，以确认在一定时间内存在药物寻求效应的潜伏期。 中期或长期停药时间点。我们将评估躯体和非躯体症状， 根据DSM-5标准和研究领域标准框架的一致性自发退出。 将使用全脑c-Fos免疫反应性的无偏映射来识别区域神经激活 与大麻素戒断和线索反应有关。我们将研究输入特异性大麻素 在NAc中确定的D1和D2中型棘神经元中，在突触的撤回诱导的可塑性 核壳耦合体外切片电生理学与光遗传学诱发的EPSC。最后我们将 利用化学遗传神经调节来测试这些回路之一对于调节复发样 行为和戒断的内在表型。这些研究将使我们了解 潜在的大麻戒断综合征，CUD的一个重要和未充分研究的方面，以及谷氨酸 突触传递和突触可塑性在戒断过程中发生改变。这可能对 对识别独特治疗靶点的意义。

PROJECT SUMMARY/ABSTRACT Cannabis is the most frequently used illicit drug in the United States. Onset of cannabis use usually occurs during adolescence, which represents a vulnerable period in neurobiological development. Due to uncertainty surrounding the long-term consequences of adolescent cannabis exposure, there is mounting concern that relaxing legal restrictions will result in increased adolescent use. Approximately 30% of users develop cannabis use disorder (CUD), and nearly half of all regular cannabis users develop cannabis withdrawal syndrome which is marked by negative affective symptoms and craving that may drive relapse. During abstinence craving may increase over time or “incubate” resulting in a period of heightened vulnerability to relapse in response to drug-related cues. Withdrawal symptoms during abstinence are clinically significant because they may impact efforts to reduce cannabis use, promote use of other substances of abuse, and adversely influence treatment outcomes. Currently there are no approved pharmacotherapies for CUD. The primary objective of this proposal is to determine how chronic cannabinoid use in adolescence impacts glutamatergic transmission and plasticity in the nucleus accumbens (NAc), and the contribution of these adaptations to later relapse-like behavior and craving. Our central hypothesis is that cannabinoid self- administration and withdrawal induces changes in glutamate transmission and synaptic connectivity in the NAc that promote negative affective processes and ultimately trigger relapse. To test this hypothesis we will use behavior, whole mount immunohistochemistry and light sheet microscopy, optogenetic aided neurophysiology, and chemogenetic manipulation techniques to assess the involvement of pathway specific glutamatergic neuroplasticity in cannabis seeking. We will use a model of adolescent intravenous D9-tetrahydrocannabinol (THC) self-administration and withdrawal to confirm the presence of an incubation of drug seeking effect at an intermediate or protracted withdrawal time point. We will assess somatic and non-somatic symptoms of spontaneous withdrawal based on alignment with DSM-5 criteria and the Research Domain Criteria framework. Unbiased mapping of whole brain c-Fos immunoreactivity will be used to identify regional neural activation associated with cannabinoid withdrawal and cue-reactivity. We will examine input-specific cannabinoid withdrawal-induced plasticity at glutamatergic synapses in identified D1 and D2 medium spiny neurons in NAc core and shell coupling in vitro slice electrophysiology with optogenetically evoked EPSCs. Finally, we will utilize chemogenetic neuromodulation to test the importance of one of these circuits for regulating relapse-like behavior and endophenotypes of withdrawal. These studies will inform our understanding of the mechanisms underlying cannabis withdrawal syndrome, an important and understudied facet of CUD, and how glutamate transmission and synaptic plasticity is altered over the course of withdrawal. This may have important implications for identifying unique therapeutic targets.