ETHANOL EFFECT ON THE BASAL FOREBRAIN CORTEX SYSTEM

乙醇对基底前脑皮层系统的影响

• 批准号: 2699662
• 负责人: MICHAEL W MILLER
• 金额: $ 19.18万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2699662
• 关键词: acetylcholinesterase; cerebral cortex; choline acetyltransferase; cytotoxicity; ethanol; gamma aminobutyrate; genetic transcription; immunocytochemistry; in situ hybridization; laboratory rat; memory; messenger RNA; neural plasticity; neuroanatomy; neurochemistry; neurotrophic factors; prosencephalon; vibrissae; western blottings

Chronic alcohol abuse leads to multiple behavioral changes and to irreversible memory loss. Recent data in rats show that ethanol-induced behavioral deficits can be ameliorated by transplantation of fetal, choline-rich tissue. These data imply that the projection from the basal forebrain to cerebral cortex is a specific target of ethanol. This projection system is one of the few to express nerve growth factor (NGF). Both NGF and acetylcholine are essential for maintaining neuronal plasticity. We hypothesize that the ethanol-induced memory loss results from losses in neuronal plasticity. This proposal describes studies which explore the structural consequences of ethanol exposure on the cholinergic system and the trophic support of basal forebrain neurons. Six experiments will be executed. (1) The effect of ethanol on the number of neurons in the basal forebrain and in the barrels of somatosensory cortex (segments which receive input from the mystacial vibrissae) will be determined using rigorous morphometric analyses. The number of neurons expressing choline acetyltrans-ferase (ChAT)[the enzyme which facilitates the synthesis of acetylcholine], acetyl-cholinesterase (AChE) [the enzyme which catalyzes the degradation of acetylcholine], and gamma-aminobutyric acid (GABA) will be determined. By using ChAT, AChE and GABA as markers for cholinergic and non-cholinergic neurons, respectively, we will be able to determine the specificity of the effects of ethanol. (2) The specificity of ethanol will further be examined by studying the effects of varying the duration of the exposure to ethanol. Are cholinergic or GABAergic neurons affected first? Does the nervous system compensate for these defects over time? If so, how? (3) The effects of ethanol on NGF and NGF receptors will be examined immunohistochemically. We will also examine the effects of ethanol on the transcription of mRNA for NGF and NGF receptors using in situ hybridization. (4) In a subsequent study, we will study the co-localization of NGF receptors in ChAT-immunoreactive neurons in the basal forebrain. (5) We will test the hypothesis that ethanol- induced changes in the cholinergic system lead to losses or impairments in neuronal plasticity. These studies will examine the effect of ethanol on the response of thalamocortical projections to peripheral damage to the vibrissae. (6) Two ways to remedy the effects of ethanol toxicity will be examined. In one study, fetal basal forebrain tissue will be transplanted into cortex, and in another, NGF will be administered. Following these manipulations, we will use the bioassays described above (tests for the specificity of the ethanol toxicity, the role of the NGF system, and the response of the nervous system to injury) to assess the success of the manipulation. Taken together, the proposed program outlines a unified battery of experiments which not only determine a mechanism of ethanol toxicity produced by chronic exposure, but also explore 2 ways in which ethanol- induced defects can be overcome.

长期酗酒会导致多种行为改变，并 不可逆转的记忆丧失。最近在大鼠身上的数据表明，乙醇诱导 行为缺陷可以通过移植胎儿， 富含胆碱的组织。这些数据表明，从基准面的投影 前脑到大脑皮层是乙醇的特定靶点。这 投射系统是少数表达神经生长因子(NGF)的系统之一。 神经生长因子和乙酰胆碱对神经元的维持都是必不可少的 可塑性。我们假设酒精导致的记忆丧失 神经元可塑性的丧失。该提案描述了以下研究 探讨酒精暴露对胆碱能神经元的结构性影响 系统与基底前脑神经元的营养支持。 将进行六个实验。(1)乙醇对细胞数量的影响 在基底前脑和躯体感觉桶中的神经元 皮质(从肌间触须接受输入的节段)将是 通过严格的形态分析确定的。神经元的数量 表达胆碱乙酰转移酶(ChAT)[促进 乙酰胆碱酯酶(AChE)的合成 其催化乙酰胆碱的降解]和γ-氨基丁酸 酸(GABA)将被测定。以ChAT、AChE和GABA为标记物 对于胆碱能和非胆碱能神经元，我们将能够 以确定乙醇作用的特异性。(2) 乙醇的特异性将通过研究乙醇的影响来进一步检验 改变接触乙醇的持续时间。胆碱能或 GABA能神经元最先受累？神经系统是否能补偿 随着时间的推移，这些缺陷呢？如果是，如何？(3)乙醇对神经生长因子和 神经生长因子受体将用免疫组织化学方法检测。我们还将检查 乙醇对神经生长因子和神经生长因子基因转录的影响 受体使用原位杂交。(4)在随后的研究中，我们会 神经生长因子受体在ChAT免疫反应神经元中的共定位研究 在基底前脑中。(5)我们将检验乙醇-- 胆碱能系统的诱导性变化会导致脑内胆碱能系统的丢失或损害 神经元的可塑性。这些研究将检验乙醇对人体健康的影响 丘脑皮质投射对周围损害的反应 触须。(6)补救酒精中毒影响的两种方法是 检查过了。在一项研究中，胎儿的基底前脑组织将被移植 进入皮质，在另一种情况下，NGF将被注射。在此之后 操作，我们将使用上述生物检测方法(测试 乙醇毒性的特异性，NGF系统的作用，以及 神经系统对损伤的反应)以评估 操纵。 综上所述，拟议的计划概述了一系列统一的 实验不仅确定了酒精毒性的机制 由长期接触产生的，但也探索了乙醇的两种方式- 诱导性缺陷是可以克服的。