The role of GIRK3 in ethanol withdrawal-induced changes in learning and memory

描述（由申请人提供）：酒精成瘾是最常见的成瘾性疾病之一，在康复的酗酒者中复发率很高。成瘾的发展和戒断后的复发与有助于学习和记忆的几个过程和神经结构有关，多方面的研究表明，酒精成瘾可能是一种适应不良的学习形式。酒精戒断严重程度是成瘾发展的指标，也是复发的主要因素。我们的实验室最近发现Kcnj 9是小鼠乙醇戒断的数量性状基因（QTG）。Kcnj 9编码G-蛋白偶联内向整流钾（GIRK）通道家族的GIRK 3/Kir3.3亚基，并且GIRK 3敲除（KO）和杂合子（HET）小鼠显示较不严重的乙醇戒断。此外，GIRK通道调节长时程增强，这是学习和记忆的细胞机制。目前建议的目标是评估GIRK 3在恐惧条件学习和记忆中的作用，并确定GIRK 3表达的变化是否会改变恐惧条件反应中戒断诱导的变化。该项目的长期目标还包括研究GIRK 3在个体学习中的作用 相关脑区在目标1中，将在急性乙醇戒断动物和对照动物中使用两种恐惧条件化范式（延迟恐惧条件化和痕量恐惧条件化）训练GIRK 3 KO、HET和野生型（WT）同窝仔。这两种形式的条件学习被认为利用不同但重叠的神经基质，使我们能够评估GIRK 3表达减少在不同学习相关脑区的影响。训练后，将评估动物对训练环境和条件刺激的冻结反应。在目标2中，将使用这两种恐惧条件反射类型在慢性乙醇戒断后训练动物，使我们能够比较GIRK 3表达对多种形式的乙醇戒断的学习和记忆的影响。这些目标不仅将确定含有GIRK 3的通道在恐惧条件学习和记忆中的作用，而且还将表征酒精戒断对学习和记忆的影响以及GIRK 3的学习效果和戒断减少效果之间的重叠程度。第三个目标将使用目标1和2的结果来确定在这些GIRK 3基因型中观察到的有助于改变戒断严重程度和学习/记忆变化的特定大脑区域。我们将使用RNAi来敲低WT小鼠单个脑区域中的GIRK 3表达，并评估敲低减弱乙醇戒断以及学习和记忆相关变化的能力。总的来说，这项工作将有助于我们了解乙醇如何改变学习和记忆系统，这是成瘾发展和复发的一个关键方面。 公共卫生相关性：酒精成瘾的发展和酗酒者康复中的高复发率与酒精引起的学习和记忆系统的变化有关。虽然学习/记忆和酒精成瘾都是由多种遗传和环境因素引起的复杂过程，但有几个研究小组报告了这两组行为的重叠染色体区域。该项目使用一种新的酒精戒断遗传模型来研究戒断引起的基于恐惧的学习和记忆的变化。

DESCRIPTION (provided by applicant): Alcohol addiction is one of the most common addictive disorders with a high rate of relapse among recovering alcoholics. The development of addiction and subsequent relapse following abstinence have been linked to several of the processes and neural structures that contribute to learning and memory, and multiple lines of research suggest that alcohol addiction may be a form of maladaptive learning. Ethanol withdrawal severity is an indicator of addiction development and a major factor in relapse. Our lab recently identified Kcnj9 as a quantitative trait gene (QTG) for ethanol withdrawal in mice. Kcnj9 codes for the GIRK3/Kir3.3 subunit of the G- protein coupled inwardly rectifying potassium (GIRK) channel family, and GIRK3 knockout (KO) and heterozygote (HET) mice show less severe ethanol withdrawal. In addition, GIRK channels modulate long-term potentiation, a cellular mechanism of learning and memory. The goal of the current proposal is to assess the role of GIRK3 in fear-conditioned learning and memory and determine if changes in GIRK3 expression alter the withdrawal-induced changes in fear conditioning responses. The long-term goals of this project also include investigating the role of GIRK3 in individual learning related brain regions. In Aim 1, GIRK3 KO, HET, and wildtype (WT) littermates will be trained using two fear conditioning paradigms (delay fear conditioning and trace fear conditioning) in acute ethanol withdrawn and control animals. These two forms of conditioned learning are thought to utilize distinct but overlapping neural substrates, allowing us to assess the effect of reduced GIRK3 expression in different learning-related brain regions. After training, animals will be assessed for freezing in response to the training context and the conditioned stimulus. In Aim 2, animals will be trained following chronic ethanol withdrawal using these two fear conditioning types, allowing us to compare the effects of GIRK3 expression on learning and memory across multiple forms of ethanol withdrawal. These aims will not only determine the role of GIRK3-containing channels in fear conditioned learning and memory, but also characterize the effect of alcohol withdrawal on learning and memory and the extent of overlap between the learning effects and the withdrawal-reducing effects of GIRK3. The third aim will use the results from Aims 1 and 2 to identify specific brain regions that contribute to the altered withdrawal severity and the learning/memory changes observed in these GIRK3 genotypes. We will use RNAi to knock-down GIRK3 expression in individual brain regions of WT mice and assess the ability of the knock-down to attenuate ethanol withdrawal and related changes in learning and memory. Overall, this work will contribute to our understanding of how ethanol alters learning and memory systems, a key aspect of addiction development and relapse. PUBLIC HEALTH RELEVANCE: The development of alcohol addiction and the high rate of relapse in recovering alcoholics have been linked to alcohol-induced changes in learning and memory systems. While both learning/memory and alcohol addiction are complex processes that result from multiple genetic and environmental factors, several groups have reported overlapping contributing chromosomal regions for these two groups of behaviors. This project uses a novel genetic model of alcohol withdrawal to investigate withdrawal-induced changes in fear-based learning and memory.