Cocaine and Brain Development

描述（由申请人提供）：该项目的长期目标是确定母体可卡因滥用对胎儿大脑发育的影响是否通过多巴胺受体信号机制的损伤介导。当前提案的具体目标是检查可卡因诱导的多巴胺受体信号的损伤是否有助于小鼠胚胎中神经元迁移的缺陷。产前可卡因暴露似乎减少了GABA神经元从神经节隆起向脑壁的迁移。多巴胺受体的激活也会影响这种迁移。产前可卡因暴露会损害多巴胺受体信号。因此，我们假设产前可卡因暴露通过损害多巴胺受体信号机制干扰GABA神经元从神经节隆起向脑壁的迁移。我们提出3个具体目标来检验我们的假设。特异性目的1将通过定量分析受体mRNA、蛋白质、结合位点、激动剂诱导的环AMP合成、CREB和DARPP 32的磷酸化来检测可卡因诱导的多巴胺受体信号传导的变化。特异性目的2将确定可卡因暴露产生的GABA神经元迁移缺陷是否可以通过电穿孔多巴胺受体构建到神经节隆起的神经元中来恢复。Specific Aim 3将使用多巴胺受体敲除小鼠，并结合功能丧失和获得来确认这些受体在神经元迁移中的作用。GABA神经元从神经节隆起迁移到脑壁，在整个大脑皮层建立抑制回路。临床研究表明，产前可卡因暴露会导致gaba介导的功能（如注意力、语言发育和学习）的持续缺陷。发育中的大脑多巴胺能系统失衡也会导致类似的损伤。因此，将GABA神经元迁移、妊娠期可卡因暴露和多巴胺受体信号传导作为实验重点具有重要的临床意义。孕妇滥用可卡因仍然是一个重大的公共卫生和社会经济问题。然而，可卡因作用于发育中的大脑的细胞和分子机制尚不完全清楚。通过研究可卡因、多巴胺和GABA回路之间的联系，拟议的研究有望为可卡因对胎儿大脑发育的作用机制提供新的见解。

DESCRIPTION (provided by applicant): The long term goals of the project are to determine if the effects of maternal cocaine abuse on fetal brain development are mediated by impairment of dopamine receptor signaling mechanisms. The specific goal of the current proposal is to examine if cocaine-induced impairment of dopamine receptor signaling contributes to deficits in neuronal migration in mouse embryos. Prenatal cocaine exposure appears to decrease GABA neuron migration from the ganglionic eminence to the cerebral wall in the embryonic mouse brain. Dopamine receptor activation also influences this migration. Prenatal cocaine exposure impairs dopamine receptor signaling. Therefore, we hypothesize that prenatal cocaine exposure interferes with GABA neuron migration from the ganglionic eminence to the cerebral wall by impairing dopamine receptor signaling mechanisms. We propose 3 Specific Aims to test our hypothesis. Specific Aim 1 will examine cocaine-induced changes in dopamine receptor signaling by quantitative analysis of receptor mRNA, protein, binding sites, agonist- induced cyclic AMP synthesis, phosphorylation of CREB and DARPP 32. Specific Aim 2 will determine if the deficits in GABA neuron migration produced by the cocaine exposure can be restored by electroporation of dopamine receptor constructs into neurons of the ganglionic eminence. Specific Aim 3 will use dopamine receptor knockout mice and a combination of loss and gain of function assays to confirm the role of these receptors in neuronal migration. The GABA neurons that migrate from the ganglionic eminence to the cerebral wall establish inhibitory circuits throughout the cerebral cortex. Clinical studies show that prenatal cocaine exposure causes lasting deficits in GABA-mediated functions, such as attention, language development and learning. Imbalance in the dopaminergic system of the developing brain also can cause similar impairments. Therefore, the focus of the proposed experiments on GABA neuron migration, gestational cocaine exposure and dopamine receptor signaling has significant clinical relevance. Cocaine abuse by pregnant women continues to be a major public health and socio-economic concern. Yet cellular and molecular mechanisms of cocaine's action on the developing brain are incompletely understood. The proposed studies promise novel insights into the mechanism of cocaine's action on fetal brain development by examining the link between cocaine, dopamine and development of GABA circuits.