In Vitro Mechanisms of Ethanol Induced Neuronal Death.

胎儿酒精效应和胎儿酒精综合症在美国金属发育迟缓和行为障碍中占很大比例，并造成巨大的个人和社会负担。了解未成熟的神经系统对乙醇的反应对于合理的干预策略至关重要。电活动促进中枢神经系统(CNS)神经元在体外和体内的存活，并防止许多中枢神经系统区域神经元的自然细胞死亡(NCD)。乙醇通过与N-甲基-D-天冬氨酸(NMDA)和γ-氨基丁酸(GABA)突触后受体相互作用来抑制中枢神经系统的电活动。因此，乙醇有可能促进发育期NCD的发生。最近的证据表明，乙醇暴露确实对活体前脑幼稚神经元有毒性。细胞丢失的模式类似于谷氨酸受体阻断和GABA受体增强的组合所产生的模式。我们的证据表明，体外培养的未成熟海马神经元也容易受到乙醇引起的细胞丢失的影响，这表明易感性是受影响的神经元群体固有的，酒精本身而不是相关的代谢或营养变量导致了神经元的丢失。培养中的海马神经元在长期暴露于GABA类似物或NMDA受体阻滞剂时也会死亡。所有这三种治疗方法都可以通过慢性去极化神经元来防止细胞死亡。因此，我们有了一个乙醇诱导的神经元死亡的体外模型，这将使我们能够探索机制问题。我们将在体外检测乙醇诱导的海马神经元死亡的超微结构和生化特征。我们将确定乙醇与NMDA受体和/或GABA受体的相互作用是否足以解释在体外观察到的神经元丢失。我们还将探讨钙信号的永久性或急性下降在细胞丢失中是否重要，并将确定细胞内钙的增加对乙醇诱导的细胞丢失提供神经保护的时间进程。拟议中的实验应该能更好地从根本上理解前脑神经元容易受到酒精诱导的死亡的机制。

Fetal alcohol effects and fetal alcohol syndrome account for a large percentage of metal retardation and behavioral disorders in the United States and impose a tremendous personal and social burden. Understanding how the immature nervous system responds to ethanol is critical to rational intervention strategies. Electrical activity promotes survival of central nervous system (CNS) neurons in vitro and in vivo and prevents natural cell death (NCD) in neurons from many CNS regions. Ethanol depresses CNS electrical activity through interactions with both N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) postsynaptic receptors. Thus it is possible that ethanol enhances developmental NCD. Recent evidence suggests that ethanol exposure is indeed toxic to immature neurons of the forebrain in vivo. The pattern of cell loss is similar to that produced by a combination of glutamate receptor blockade and GABA receptor potentiation. Our evidence suggests that immature hippocampal neurons in vitro are also susceptible to ethanol- induced cell loss, suggesting that susceptibility is intrinsic to neuronal populations affected and that ethanol itself, rather than associated metabolic or nutritional variables, induces the neuronal loss. Hippocampal neurons in culture also die when chronically exposed to GABAmimetics or NMDA receptor blockade. Cell death elicited by all three treatments is prevented by chronically depolarizing neurons. Thus, we have an in vitro model of ethanol-induced neuronal death that will allow us to explore mechanistic questions. We will examine the ultrastructural and biochemical profile of ethanol-induced hippocampal neuronal death in vitro. We will determine whether the interaction of ethanol with NMDA receptors and/or GABA receptors is sufficient to explain the neuronal loss observed in vitro. We will also address whether permanent or acute decreases in calcium signaling are important in cell loss and will determine the time course over which increases in intracellular calcium provide neuroprotection against ethanol-induced cell loss. The proposed experiments should lead to a better fundamental understanding of the mechanisms by which forebrain neurons are susceptible to ethanol-induced death.