Endocannabinoid Signaling in Postnatal Ethanol Effects

描述（由申请方提供）：已知乙醇暴露对发育中的胎儿有不良影响。在人类妊娠晚期（啮齿动物出生后1-14天）的突触发生期间使用乙醇会引发凋亡性细胞死亡。乙醇的使用影响海马功能，损害突触可塑性、学习和记忆。我们在KO 1奖期间的工作导致了这样的假设，即乙醇通过增加海马神经元中内源性大麻素[EC;花生四烯酸（AEA）和2-花生四烯酸甘油（2-AG）]的产生来对突触可塑性产生影响。大麻素（CB）本身，如乙醇抑制突触可塑性，并显着加剧乙醇在发育中的大脑中的凋亡作用。在早期脑发育过程中，CB介导的突触活动似乎会影响认知缺陷的脑成熟途径。然而，乙醇影响EC偶联途径的细胞机制在很大程度上仍然未知。我们的初步数据表明，在突触形成期间给予乙醇激活大麻素1型（CB 1 R）受体诱导神经变性。此外，增强的CB 1 R活性导致成年动物中pCREB水平和突触可塑性的缺陷。CB 1 R阻断可挽救新生小鼠的神经变性它还挽救了在成年动物中观察到的突触功能障碍。我们有希望的初步数据，涉及EC和CB 1 R介导的机制，强调了这一研究方向的重要性。我们的中心假设是，乙醇介导的激活海马CB 1 R通路在突触形成的结果在突触可塑性的长期赤字。我们提出了三个具体目标来解决这个假设。该方法结合了CB 1 R敲除小鼠的使用和已建立的免疫学、生物化学方法和电生理学技术。在具体目标1中，我们将研究突触发生期间出生后乙醇给药对AEA和2-AG代谢命运以及CB 1 Rs表达和功能的影响。在具体目标2中，我们将研究出生后乙醇效应如何与CB 1 R依赖性信号通路相结合。在具体目标3中，我们将测试出生后早期乙醇暴露是否会导致成年动物海马突触可塑性的长期抑制。了解海马体中EC通路的分子基础将有助于开发潜在的CB 1 R靶向策略，用于治疗海马异常和记忆和学习缺陷，这些异常和学习缺陷通常是由怀孕期间酗酒引起的。 公共卫生相关性：希望更好地了解中枢神经系统发育过程中乙醇暴露如何改变海马中的内源性大麻素途径，将导致更有效的治疗海马异常和相关的记忆和学习缺陷的策略，由于怀孕期间滥用酒精，代表了西方世界最常见的发育障碍。此外，拟议研究的结果可供医疗保健专业人员用于咨询孕妇饮酒的潜在影响。

DESCRIPTION (provided by applicant): Ethanol exposure is known to have adverse effects on the developing fetus. Ethanol use during the synaptogenesis period, which occurs over the third trimester of pregnancy in humans (1-14 days after birth in rodents), triggers apoptotic cell death. The use of ethanol affects hippocampal functions impairing synaptic plasticity, learning and memory. Our work during the KO1 award period has led to the hypothesis that ethanol exerts its effects on synaptic plasticity via increased production of endogenous cannabinoids [ECs; anandamide (AEA) and 2-arachidonylglycerol (2-AG)] in hippocampal neurons. Cannabinoids (CB) themselves, like ethanol inhibit synaptic plasticity and markedly exacerbate the apoptotic effects of ethanol in the developing brain. The CB-mediated synaptic activity during early brain development seems to affect brain maturation pathways that influence cognitive deficits. However, the cellular mechanism(s) by which ethanol affects EC-coupled pathways remains largely unknown. Our preliminary data suggest that ethanol administration during the synaptogenic period activates the cannabinoid type 1 (CB1R) receptor inducing neurodegeneration. In addition, the enhanced CB1R activity causes deficits in pCREB levels and synaptic plasticity in adult animals. The CB1R blockade rescues neurodegeneration in neonatal mice. It also rescues the synaptic dysfunction observed in adult animals. Our promising preliminary data, implicating ECs and CB1R-mediated mechanisms, underscores the importance of this research direction. Our central hypothesis is that ethanol-mediated activation of hippocampal CB1R pathways during synaptogenesis results in long-lasting deficits in synaptic plasticity. We propose three Specific Aims to address this hypothesis. The approach combines the use of CB1R null mice and the established immunological, biochemical methods and electrophysiology techniques. In Specific Aim 1, we will investigate the effects of postnatal ethanol administration during the synaptogenesis period on the metabolic fate of AEA and 2-AG, and CB1Rs expression and function. In Specific Aim 2, we will investigate as to how postnatal ethanol effects are coupled to the CB1R-dependent signaling pathways. In Specific Aim 3, we will test whether the early postnatal ethanol exposure causes long lasting depression of hippocampal synaptic plasticity in adult animals. Understanding the molecular underpinnings of the EC pathway (s) in the hippocampus will help to develop potential CB1R targeted strategies for treating hippocampal abnormalities and memory and learning deficits that often result from alcohol abuse during pregnancy. PUBLIC HEALTH RELEVANCE: It is hoped that better understanding of how ethanol exposure during CNS development alters endocannabinoid pathways in the hippocampus will lead to more effective strategies for the treatment of hippocampal abnormalities and related memory and learning deficits in children due to alcohol abuse during pregnancy, representing the most common developmental disability in the Western world. Additionally, the results of the proposed studies may be used by health care professionals in counseling pregnant women on the potential effects of alcohol consumption.