Ethanol and the Developing Cerebellum

描述（由申请方提供）：大鼠出生后第4-6天（PN 4 -6）的发育期乙醇暴露是妊娠晚期早期的人类暴露模型，导致小脑浦肯野神经元丢失以及运动技能和眨眼条件反射功能缺陷。在人类FASD中也观察到类似的损伤。攀缘纤维来自浦肯野细胞上的下橄榄突触，是正常功能的组成部分。很少有研究涉及乙醇暴露集中在攀爬纤维的作用。我们假设，乙醇暴露在出生后早期（发育）阶段的小脑通过改变突触连接的浦肯野细胞攀爬纤维，独立的神经元损失的幸存的神经元成分产生负面影响。我们还推测，乙醇诱导的特定类别的谷氨酸受体的改变是机械地参与这些变化。我们将利用共聚焦显微镜检查这些神经元结构的3-D形态和乙醇诱导的改变的程度，因为它们的发展和成熟。我们提出了以下具体目标：（1）建立攀爬纤维的改变后，出生后乙醇暴露独立的浦肯野神经元的损失。我们将在PN 4、PN 4 6和PN 7 9使用乙醇处理的大鼠。浦肯野神经元仅在PN 4 -6窗口期间易受乙醇暴露的影响。(2)评价出生后乙醇暴露后存活的浦肯野细胞的形态发育。我们将描述与对照组相比，接受不同发育暴露于乙醇的大鼠组中存活浦肯野细胞的索马和树突树的形态发育。这项深入的分析将为这些幸存的浦肯野神经元提供第一个这样的数据。(3)确定是否谷氨酸受体亚型，AMPA和mGluR，乙醇诱导的攀爬纤维发育的改变的因果机制。我们将探讨谷氨酸受体和攀爬纤维发育连接之间的机制联系，通过管理谷氨酸受体阻滞剂与乙醇暴露和不同时。我们认为，乙醇的作用的一个重要组成部分是通过在关键发育时期阻断这些受体介导的。我们的重点是小脑结构的状态和持续发展，这些结构在已知会导致显著神经元死亡的酗酒样乙醇损伤中幸存下来。这项工作的最终目标是从这些知识中获得最大限度地利用这些剩余结构的手段或方法，为个人提供最佳结果。由于没有治疗干预将取代失去的浦肯野细胞，在攀爬纤维和幸存的浦肯野神经元之间的复杂连接的变化的特性和性质的理解持有改善治疗患有FASD的儿童的希望。

DESCRIPTION (provided by applicant): Developmental ethanol exposure, involving postnatal days 4-6 (PN4-6) in rats, is a model of human exposure during the early third trimester and results in loss of Purkinje neurons of the cerebellum and functional deficits in motor skills and eye blink conditioning. Similar impairments are seen in human FASD. Climbing fibers from the inferior olive synapse on Purkinje cells and are an integral component for proper functioning. Few studies involving ethanol exposure have focused on the role of climbing fibers. We hypothesize that ethanol exposure in the early postnatal (developmental) stage negatively impacts the surviving neuronal components of the cerebellum by altering synaptic connections of the Purkinje cells to climbing fibers, independent of neuronal loss. We also theorize that ethanol-induced alterations in specific classes of glutamate receptors are mechanistically involved in these changes. We will utilize confocal microscopy to examine the 3-D morphology of these neuronal structures and the extent of ethanol-induced alterations, as they develop and mature. We propose the following Specific Aims: (1) Establish that climbing fibers are altered following postnatal ethanol exposure independent of Purkinje neuron loss. We will use rats treated with ethanol on PN4, PN4 6, and PN7 9. Purkinje neurons are vulnerable to ethanol exposure only during the PN4-6 window. (2) Evaluate the morphological development of Purkinje cells that survive postnatal ethanol exposure. We will characterize the morphological development of the soma and the dendritic tree of the surviving Purkinje cells in groups of rats receiving varying developmental exposures to ethanol compared to a control group. This in-depth analysis will provide the first such data for these surviving Purkinje neurons. (3) Determine whether the glutamate receptor subtypes, AMPA and mGluR, are causal mechanisms of ethanol-induced alterations of climbing fiber development. We will explore the mechanistic link between glutamate receptors and climbing fiber developmental connections by administering glutamate receptor blockers with and without concurrent ethanol exposure. We believe that a significant component of ethanol's actions is mediated by its blockage of these receptors during critical developmental periods. Our focus is on the status and continued development of the cerebellar structures that have survived the binge-like ethanol damage delivered at a time known to cause significant neuronal death. The ultimate goal of this work is then to derive from this knowledge a means or method for the maximum utilization of these remaining structures to provide the best outcome for the individual. Since no therapeutic intervention will replace the lost Purkinje cells, an understanding of the characteristics and nature of alterations in the intricate connections between climbing fibers and the surviving Purkinje neurons holds the promise of ameliorative treatments for children suffering from FASD.