Ethanol and Persistent Activity in Prefrontal Cortex

乙醇与前额皮质的持续活动

• 批准号: 7226878
• 负责人: JOHN J. WOODWARD
• 金额: $ 15.93万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7226878
• 关键词: AMPA receptors; GABA receptor; NMDA receptors; alcoholism /alcohol abuse; alcoholism /alcohol abuse chemotherapy; confocal scanning microscopy; dopamine; drug withdrawal; ethanol; fluorescent dye /probe; hippocampus; laboratory rat; mixed tissue /cell culture; neurochemistry; neurophysiology; neuroregulation; neurotransmitter transport; prefrontal lobe /cortex; pyramidal cells; receptor expression; tegmentum; voltage /patch clamp

Alcoholism is characterized by a loss of control over drinking that may result from long-lasting alterations in higher cortical circuits that normally control compulsive behaviors. Brain imaging studies show that, in alcoholics, the prefrontal cortex (PFC) displays functional alterations during abstinence or after exposure to ethanol (EtOH) or visual cues associated with drinking. Little, however, is known about the actions of EtOH on prefrontal function at the cellular level. In this project, we will investigate the effects of acute and chronic EtOH exposure on the function of excitatory pyramidal neurons of the prefrontal cortex. A hallmark of prefrontal cortical neurons is "persistent activity" characterized by spontaneous and rhythmic transitions between a hyperpolarized down-state in which firing is inhibited and a depolarized up-state that is conducive for generating action potentials. The firing activity during up-state periods is modulated by dopaminergic input from VTA neurons that synapse on layer V prefrontal cortical neurons. Persistent activity may allow the prefrontal cortex to exert higher-order control over the addiction neurocircuitry by integrating and processing sensory information derived from internal and external cues. Disruption of persistent activity states within the prefrontal cortex by EtOH may be a primary event in the loss of control over compulsive drinking behaviors. Persistent activity has been studied in anesthetized whole animals but it does not occur in reduced systems such as acutely isolated slices of cortex. To circumvent problems associated with anesthesia and to allow for precise analysis of putative mechanisms, we have adapted a slice co-culture system containing prefrontal cortex, VTA, and hippocampus. After 2 weeks in culture, prefrontal neurons in this system display robust and reproducible patterns of persistent activity that can modulated by stimulusevoked firing of VTA dopamine neurons. The major goal of this project is to determine the effects of acute and chronic ethanol exposure on persistent activity of PFC neurons using this co-culture system. Aims 1, 2 and 3 will use patch-clamp electrophysiology to analyze the effects of acute and chronic ethanol on spontaneous and VTA-evoked persistent activity in layer V prefrontal pyramidal neurons. Aim 4 will use confocal imaging techniques to assess the effects of ethanol on pyramidal cell activity at the network level. The results of these studies will yield important new information regarding ethanol's effects on brain function.

酗酒的特点是对饮酒失去控制，这可能是由于长期持续的改变而导致的 通常控制强迫行为的高级皮层回路。脑成像研究表明，在 酗酒者的前额皮质（PFC）在戒酒期间或接触酒精后表现出功能改变 乙醇 (EtOH) 或与饮酒相关的视觉提示。然而，人们对 EtOH 的作用知之甚少 细胞水平上的前额叶功能。在这个项目中，我们将研究急性和慢性的影响 乙醇暴露对前额皮质兴奋性锥体神经元功能的影响。一个标志 前额皮质神经元是“持续活动”，其特征是自发和有节奏的转换 介于抑制发射的超极化向下状态和有利于发射的去极化向上状态之间 用于产生动作电位。上状态期间的放电活动受多巴胺能调节 来自 VTA 神经元的输入，这些神经元突触在 V 层前额皮质神经元上。持续的活动可能会让 前额皮质通过整合和对成瘾神经回路施加高阶控制 处理来自内部和外部线索的感官信息。持续活动的中断 乙醇导致的前额皮质内的状态可能是强迫症失控的主要事件 饮酒行为。已在麻醉的整只动物中研究了持久活性，但并未发生 在简化的系统中，例如急剧分离的皮质切片。为了规避相关问题 麻醉并允许精确分析假定的机制，我们采用了切片共培养 系统包含前额皮质、腹侧被盖区和海马体。培养两周后，前额叶神经元 该系统显示出稳健且可重复的持续活动模式，可以通过刺激诱发进行调节 VTA 多巴胺神经元的放电。该项目的主要目标是确定急性发作的影响 以及慢性乙醇暴露对使用该共培养系统的 PFC 神经元持续活动的影响。目标 1、2 3 将使用膜片钳电生理学来分析急性和慢性乙醇对 V 层前额锥体神经元自发和 VTA 诱发的持续活动。目标4将使用 共聚焦成像技术评估乙醇对网络水平锥体细胞活性的影响。 这些研究的结果将产生有关乙醇对大脑功能影响的重要新信息。