Mechanisms of rostrocaudal differences in accumbal kappa opioid receptor effects on ethanol drinking

项目摘要 在酒精使用障碍（AUD）中，酒精消费部分是由负强化驱动的： 消极的情感状态这种负强化在一定程度上是由强啡肽/κ阿片样物质控制的。 受体（KOR）系统，涉及单胺类、5-羟色胺（5-HT）和多巴胺（DA）。跨多个 研究发现，大脑区域中KOR的激活会引起厌恶状态，对于大脑区域来说也是如此。 尾侧亚区的丘脑核（NAc）壳。然而，奇怪的是，KOR激活在吻侧， NAC壳牌被发现是值得的。我们的初步数据，使用乙醇饮用模型， 过渡到依赖性，表明吻侧NAc壳中的KOR激活促进接近行为， 减弱乙醇饮用，而尾壳中的激活反而促进回避行为和乙醇 喝酒此外，虽然DA和5-HT传入终止于喙壳和尾壳，但KOR远没有终止。 对尾壳DA释放的抑制作用更大。我们假设，在吻侧皮层KOR的激活， NAc壳通过优先调节5-HT相对于DA，增强享乐状态并抑制饮酒; 相反，尾侧NAc壳中的KOR激活驱动烦躁状态并增加乙醇饮用， 相对于5-HT优先调节DA。目的1研究了KOR激活的具体假设， 喙壳减少酒精饮用，并诱导积极的影响，与平衡的KOR控制， 单胺释放倾向于5-HT。为了实现这一点，拟议的实验，在喙NAc壳， 将使用药理学来确定KOR激活对（1）饮酒和（2）接近/回避的影响 行为，分子生物学，以（3）检查DA和5-HT末端上的KOR分布，以及 电化学技术来测量KOR活化对光刺激的（4）DA和（5）5-HT的影响。 目的2研究尾壳KOR激活增强乙醇饮用的特定假设 和负面影响，与KOR有他们的主要影响DA。为了实现这一点，拟议的实验， 在尾侧NAc壳中，将确定KOR激活对（1）乙醇饮用和（2） （3）检测DA和5-HT末梢上KOR的分布，并测量 KOR激活对光刺激的（4）DA和（5）5-HT的影响。目标3阐明了驱动机制 这些对行为的矛盾影响。它研究了KOR介导的5-羟色胺抑制的具体假设， NAc壳中的HT活性抑制乙醇消耗，而DA活性的抑制则相反， 5-HT和DA抑制的这些作用分别在喙壳和尾壳中最明显。因此，在本发明中， 所提出的实验将检测病毒KOR表达选择性地对（1）DA和（2）的行为影响。 5-HT终末在喙壳和尾壳，和化学发生抑制（3）DA和（4）5-HT投射到 这些次区域。了解KOR系统的各种功能最终可以促进设计 途径特异性疗法，彻底改变了AUD的治疗方法。

PROJECT SUMMARY In alcohol use disorder (AUD), alcohol consumption is driven, in part, by negative reinforcement: the removal of the negative affective state. This negative reinforcement is governed, in part, by the dynorphin/kappa opioid receptor (KOR) system and involves the monoamines, serotonin (5-HT) and dopamine (DA). Across multiple brain regions, activation of KORs has been found to elicit a state of aversion, and this is also the case for the nucleus accumbens (NAc) shell, in the caudal subregion. Paradoxically, however, KOR activation in the rostral NAc shell has been found to be rewarding. Our preliminary data, using a model of ethanol drinking that reflects the transition to dependence, show that KOR activation in the rostral NAc shell promotes approach behavior and attenuates ethanol drinking, while activation in the caudal shell instead promotes avoidance behavior and ethanol drinking. Moreover, while DA and 5-HT afferents terminate in both the rostral and caudal shell, KORs have far greater inhibitory effects on DA release in the caudal shell. We hypothesize that activation of KORs in the rostral NAc shell elicits a hedonic state and inhibits ethanol drinking, by preferentially modulating 5-HT vs. DA; in contrast, KOR activation in the caudal NAc shell drives a dysphoric state and increases ethanol drinking, by preferentially modulating DA vs. 5-HT. Aim 1 investigates the specific hypothesis that KOR activation in the rostral shell reduces ethanol drinking and induces positive affect, with the balance of KOR control over monoamine release tipped towards 5-HT. To accomplish this, the proposed experiments, in the rostral NAc shell, will use pharmacology to determine effects of KOR activation on (1) ethanol drinking and (2) approach/avoidance behavior, molecular biology to (3) examine the distribution of KORs on DA and 5-HT terminals, and electrochemical techniques to measure effects of KOR activation on optically stimulated (4) DA and (5) 5-HT. Aim 2 investigates the specific hypothesis that KOR activation in the caudal shell potentiates ethanol drinking and negative affect, with KORs having their major effects on DA. To accomplish this, the proposed experiments, in the caudal NAc shell, will determine effects of KOR activation on (1) ethanol drinking and (2) approach/avoidance behavior, (3) examine the distribution of KORs on DA and 5-HT terminals, and measure effects of KOR activation on optically stimulated (4) DA and (5) 5-HT. Aim 3 clarifies the mechanism driving these paradoxical effects on behavior. It investigates the specific hypothesis that KOR-mediated inhibition of 5- HT activity in the NAc shell inhibits ethanol consumption, while inhibition of DA activity does the opposite, and that these effects of 5-HT and DA inhibition are most apparent in the rostral and caudal shell, respectively. Thus, the proposed experiments will examine behavioral effects of viral KOR expression selectively on (1) DA and (2) 5-HT terminals in the rostral and caudal shell, and chemogenetic inhibition of (3) DA and (4) 5-HT projections to these subregions. Understanding the diverse functions of the KOR system could ultimately facilitate the design of pathway-specific therapeutics, revolutionizing treatment for AUD.