Impact of prenatal opioid exposure on long-range brain circuit connectivity and behavior

项目摘要 2010年，美国估计有600万人滥用处方止痛药， 目前的阿片类药物流行病。此外，据估计，美国10-20%的妇女每人都有一个处方。 一年的阿片类药物，如羟考酮（氧），在怀孕期间。总的来说，这导致了五倍的 在过去十年中，孕妇使用处方药的情况有所增加， 在阿片类药物戒断中，每15分钟发生一次，称为新生儿戒断综合征（NAS）。尽管增长迅速， 出生时患有NAS的人群，产前暴露于阿片类药物对 大脑发育以及终身行为影响的定义很差。更好地确定 产前OXY暴露对神经回路和行为发育的影响将允许未来的研究 深入到潜在的机制中长期目标是制定新颖和创新的战略， 减轻终身影响，目前对OXY的关注特别是基于感知的安全性， FDA批准的状态。在子宫内暴露于OXY的成年小鼠中进行的一系列广泛的行为测试 表明这种发展性的侮辱会产生与冲动控制和反应有关的行为缺陷， 具有性别特异性效应的阿片类药物，这与关于接触阿片类药物的儿童的有限数据一致。 子宫内的阿片类药物内侧前额叶皮层（mPFC）是控制这些神经回路的核心成员。 行为，通常与由纹状体和杏仁核驱动的额叶功能减退有关。因此， 一种假设是，产前氧改变了长距离输入到前额叶皮层的发展， 行为失调为了开始解决这一问题，在20名受试者中进行了无偏单突触回路追踪。 GAD 2-Cre小鼠在两种性别中创建对mPFC抑制的所有直接、长距离输入的全脑地图 神经元与前额叶功能减退的可能性相一致，该分析揭示了一个显著的和选择性的 女性基底外侧杏仁核（BLA）与mPFC中间神经元（IN）的结构连接性升高 产前接触过氧气这导致了这里要解决的工作假设，即产前氧合 暴露产生BLA介导的mPFC抑制，导致行为失调。完成 这两个提出的目标预计将产生以下结果：（1）单突触的无偏全脑地图 在产前背景下对兴奋性和抑制性（PV、SST和VIP+）mPFC神经元的长程输入 氧暴露，以确定这些输入的来源和平衡。(2)确定BLA的影响力 在产前OXY暴露后的mPFC，在功能连接方面，使用高密度硅 光遗传学刺激和行为的探针，使用化学遗传学。预计拟议的研究将 为未来的机制研究提供了一个框架，旨在进一步定义功能子电路，如何 最好地减轻母体阿片类药物使用的后果，并评估当前NAS干预措施的影响 在NICU中使用，其中包括产后阿片类药物替代疗法。

PROJECT SUMMARY In 2010, an estimated 6 million individuals in the United States abused prescription pain relievers, triggering the current opioid epidemic. Further, an estimated 10-20% of women in the U.S. receive a prescription each year for an opioid, such as oxycodone (OXY), during pregnancy. Collectively, this has resulted in a five-fold increase in prescription drug use among expectant mothers over the last decade, as well as one baby born every 15 minutes in opioid withdrawal, termed neonatal abstinence syndrome (NAS). Despite a rapidly growing population of individuals born with NAS, basic research efforts on the effects of prenatal exposure to opioids on brain development, as well as the lifelong behavior impacts, are poorly defined. Better identifying the effects of prenatal OXY exposure on the development of neural circuits and behavior will allow for future investigations into the underlying mechanisms. The long-term goal is development of novel and innovative strategies to mitigate the lifelong impact and the current focus on OXY specifically is based on the perceived safety due to its FDA-approved status. A broad battery of behavioral tests performed in adult mice exposed to OXY in utero indicates this developmental insult produces behavioral deficits related to impulse control and response to opioids, with sex-specific effects, that are consistent with the limited data available on children exposed to opioids in utero. The medial prefrontal cortex (mPFC) is a core member of the neural circuitry governing these behaviors, often with a link to hypofrontality driven by the striatum and amygdala. Thus, the overarching hypothesis is that prenatal OXY alters the development of long-range inputs to the prefrontal cortex, resulting in behavioral dysregulation. To begin addressing this, unbiased monosynaptic circuit tracing was performed in GAD2-Cre mice to create whole brain maps in both sexes of all direct, long-range inputs to mPFC inhibitory neurons. Consistent with the possibility of hypofrontality, this analysis revealed a marked and selective elevation in structural connectivity to mPFC interneurons (INs) from the basolateral amygdala (BLA) in females exposed to prenatal OXY. This led to the working hypothesis to be addressed here, that prenatal OXY exposure produces BLA-mediated inhibition of the mPFC, resulting in behavioral dysregulation. Completion of the two proposed Aims is expected to produce the following: (1) Unbiased whole brain maps of monosynaptic long-range inputs to excitatory and inhibitory (PV, SST and VIP+) mPFC neurons in the context of prenatal OXY exposure, to determine the source and balance of these inputs. (2) Determination of the BLA’s influence over the mPFC following prenatal OXY exposure, in terms of functional connectivity, using high density silicon probes with optogenetic stimulation and behavior, using chemogenetics. The proposed research is expected to provide a framework for future mechanistic studies aimed at further defining the functional subcircuits, how to best mitigate the consequences of maternal opioid use and assessing the impact of current NAS interventions employed in NICUs, which consists of postnatal opioid replacement therapies.