Impact of alterations in mesolimbic innervation of the prefrontal cortex following adolescent alcohol exposure.

项目总结 在青春期酗酒的人更有可能患上慢性复发性酒精 在他们生命中的某个时候会出现紊乱。对动物的研究也表明，反复发作的青春期 酒精暴露导致内侧前额叶皮质(PFC)调节失调，抑制控制和功能障碍 成年后的行为灵活性。这项提议的目标是利用青少年间歇性啮齿动物模型 酒精暴露(AIE)研究酒精所致前额叶功能障碍的机制 成年后的行为控制。最近的研究表明腹侧被盖区(VTA)的一个子集 最初支配伏核(NAC)的多巴胺能投射神经元随后生长到 PFC，这一过程对成年后的执行功能非常重要。虽然我们的实验室已经证明了AIE 显著影响PFC前部(PRL)亚区的多巴胺能神经传递和调节， 目前尚不清楚新发现的VTA-NAC-PRL通路是否会因AIE暴露而改变。突触修剪在大脑中的作用 青春期的内侧PFC和NAC对于抑制控制和行为灵活性至关重要。有趣的是， 越来越多的数据表明，这一过程是通过胶质细胞介导的吞噬作用来促进的。尽管它是 已知酒精可以改变神经免疫信号，AIE暴露是否影响神经胶质/神经相互作用和 神经胶质细胞的形态还不是很清楚。当前提案的首要假设是，AIE暴露 减少PRL皮质中的VTA神经支配和神经/胶质细胞的相互作用，导致成人的改变 行为。特定目标1将检验AIE暴露降低发育神经和 PRL皮质中VTA起源的DA投射的突触细化。这个目标将使用轴突启动的病毒 转导、免疫荧光、先进的超分辨率共聚焦显微镜和3D分析 观察VTA-DA神经元对PRL的神经支配，这些神经元的轴突最初终止于NAC，然后生长 在青春期到PRL。为了对PRL-NAC电路内的变化有更广阔的视角 在AIE之后，研究还将检查神经胶质与PRL神经元的相互作用，这些神经元投射回NAC。特定的 目标2将检验这一假设，即AIE和抑制VTA-NAC-PRL投射同样会改变活动和 成年期的消极回避。这一目标将深入了解AIE和VTA-NAC-PRL预测的影响 关于行为的灵活性。新的平台中介的回避任务允许同时进行调查 被动和主动回避，这是发展文献中关于AIE的一个领域，相对 被忽视了。研究还将确定DREADD介导的VTA-NAC-PRL途径的抑制 以类似于AIE的方式改变成人的回避行为。这项提议的新概念性质，在 结合最先进的技术和出色的培训资源，将为PI提供 增加的技能将进一步推动未来成为一名独立的学术研究人员。

PROJECT SUMMARY Individuals that binge drink alcohol during adolescence are more likely to develop chronic, relapsing alcohol disorders at some point in their life. Studies in animals have also shown that repeated episodes of adolescent alcohol exposure lead to dysregulation of the medial prefrontal cortex (PFC) and deficits in inhibitory control and behavioral flexibility in adulthood. The goal of this proposal is to utilize a rodent model of adolescent intermittent ethanol (AIE) exposure to investigate mechanisms involved in alcohol-induced deficits in prefrontal function and behavioral control in adulthood. Recent research suggests that a subset of ventral tegmental area (VTA) dopaminergic projection neurons that initially innervate the nucleus accumbens (NAc) subsequently grow to the PFC, a process that is important for executive function in adulthood. While our lab has shown that AIE significantly impacts dopaminergic neurotransmission and regulation in the prelimbic (PrL) subregion of the PFC, it is unknown if the newly identified VTA-NAc-PrL pathway is altered by AIE exposure. Synaptic pruning in the medial PFC and NAc during adolescence is critical for inhibitory control and behavioral flexibility. Interestingly, accumulating data indicates that this process is facilitated through glial-mediated phagocytosis. Although it is known that alcohol can alter neuroimmune signaling, whether AIE exposure affects glial/neural interactions and glial morphology is not well understood. The overarching hypothesis of the current proposal is that AIE exposure reduces VTA innervation and neural/glial interactions in the PrL cortex, contributing to alterations in adult behavior. Specific Aim 1 will test the hypothesis that AIE exposure reduces the developmental innervation and synaptic refinement of VTA originating DA projections in the PrL cortex. This aim will use axon-initiated viral transduction, immunofluorescence, and advanced super-resolution confocal microscopy and 3D analysis to examine innervation of the PrL by VTA-DA neurons whose axons initially terminated in the NAc and then grew to the PrL during adolescence. In order to gain a broader perspective of alterations within the PrL-NAc circuit following AIE, studies will also examine glial interactions with PrL neurons that project back to the NAc. Specific Aim 2 will test the hypothesis that AIE and inhibition of the VTA-NAc-PrL projection will similarly alter active and passive avoidance in adulthood. This aim will gain insight into the impact of AIE and the VTA-NAc-PrL projection on behavioral flexibility. The novel platform-mediated avoidance task allows for the simultaneous investigation of both passive and active avoidance, an area in the developmental literature on AIE that has been relatively overlooked. Studies will also determine whether DREADD-mediated inhibition of the VTA-NAc-PrL pathway alters adult avoidance behavior in a similar manner to AIE. The novel conceptual nature of this proposal, in combination with state-of-the-art techniques and outstanding training resources will provide the PI with an increased skill set that will further the advancement towards a future as an independent academic researcher.