DAT-Regulation of Nucleus Accumbens Microcircuitry by Oxycodone Exposure and Withdrawal

DAT18-07：戒烟的厌恶性是负面强化的一个强大来源， 使羟考酮和其他处方类阿片的使用和滥用永久化。更有效的缓解战略 防止戒断可能会减少处方阿片类药物的消费，并有助于停止努力 使用并防止复发。这些策略必须通过对神经回路的更深层次的了解来了解 调解处方阿片类药物戒断的厌恶和其他方面。我们研究的长期目标是 确定阿片类药物暴露和戒断如何改变伏隔核抑制微电路，以及 最终，利用这些知识来逆转或防止导致上瘾的适应不良变化。这个 伏隔核通常与奖赏有关，但也有“黑暗面”，导致厌恶 阿片类药物戒断和其他厌恶状态的方面。这项提案的具体目标是评估 伏核快速放电中间神经元(FSIS)和中棘神经元(MSN)在中枢神经系统中的作用 在羟考酮戒断过程中的厌恶行为，并确定羟考酮戒断如何改变细胞 FSIS和MSN的属性。这项建议的科学前提是基于已公布的初步数据。 伏隔核FSIS和D2-MSN在阿片类药物戒断过程中被激活，并调节厌恶状态。 我们的中心假设是，FSIS被阿片类药物暴露抑制，并在阿片类药物期间表现出反弹激活 戒断，通过GABA能突触调节厌恶情绪到MSN。我们预测慢性病 羟考酮暴露可重组FSIS向MSN的突触输出，改变FSIS调节厌恶的方式。在……里面 目标1，我们将确定FSIS、D2-MSN和D1-MSN在羟考酮过程中如何调节厌恶 戒烟。使用一个临床相关的自发性羟考酮戒断模型，我们将使用化学遗传学 方法操纵FSIS和MSN的活动，并测量条件性位置厌恶和经典的 身体上有戒断的迹象。我们还将确定FSI操作如何调节MSN的激活。我们 预测FSI激活通过抑制作用抑制羟考酮戒断的表达 D2-MSNS。在AIM 2中，我们将确定FSIS和MSN的细胞属性如何通过 羟考酮停药。羟考酮连续暴露一周后，我们将制备急性脑片 在羟考酮存在的情况下，并通过将脑片暴露于纳洛酮而在体外迅速戒断。我们 在戒断过程中，预计会发现FSIS向D2-MSN释放GABA的增加，这是一种神经可塑性变化 这将解释为什么FSIS会在撤资期间抑制厌恶情绪。我们还将测量细胞的运动轨迹 体内反复撤药后的变化，并预测FSIS和MSN在每次撤药过程中的周期性参与 戒断事件会在伏隔核内产生持久的、不适应的神经可塑性。 这些实验的成功完成将揭示伏隔核FSIS在阿片类药物中的新作用 这些细胞代表了缓解阿片类药物戒断状态的新的治疗靶点。

DAT18-07: The aversive nature of withdrawal represents a powerful source of negative reinforcement, perpetuating the use and abuse of oxycodone and other prescription opioids. More effective strategies to relieve and prevent withdrawal may decrease consumption of prescription opioids, and facilitate efforts to discontinue use and prevent relapse. These strategies must be informed by a deeper understanding of the neural circuits mediating aversion and other facets of prescription opioid withdrawal. The long-term goal of our research is to determine how opioid exposure and withdrawal modify nucleus accumbens inhibitory microcircuits, and ultimately use this knowledge to reverse or prevent maladaptive changes that contribute to addiction. The nucleus accumbens is commonly associated with reward but also has a “dark side”, contributing to the aversive aspects of opioid withdrawal and other states of aversion. The specific goals of this proposal are to evaluate the contribution of nucleus accumbens fast-spiking interneurons (FSIs) and medium spiny neurons (MSNs) to aversive behavior during oxycodone withdrawal, and determine how oxycodone withdrawal modifies cellular properties of FSIs and MSNs. The scientific premise for this proposal is based on published and preliminary data that nucleus accumbens FSIs and D2-MSNs are activated during opioid withdrawal and regulate aversive states. Our central hypothesis is that FSIs are inhibited by opioid exposure and exhibit rebound activation during opioid withdrawal, modulating aversion through their GABAergic synapses onto MSNs. We predict that chronic oxycodone exposure reorganizes synaptic output of FSIs onto MSNs, changing how FSIs regulate aversion. In AIM 1, we will determine how FSIs, D2-MSNs, and D1-MSNs regulate aversion during oxycodone withdrawal. Using a clinically relevant model of spontaneous oxycodone withdrawal, we will use chemogenetic methods to manipulate the activity of FSIs and MSNs, and measure conditioned place aversion as well as classic somatic signs of withdrawal. We will also determine how FSI manipulations regulate the activation of MSNs. We predict that FSI activation constrains the expression of oxycodone withdrawal through an inhibitory influence on D2-MSNs. In AIM 2, we will determine how the cellular properties of FSIs and MSNs are altered by oxycodone withdrawal. After continuous oxycodone exposure for one week, we will prepare acute brain slices in the presence of oxycodone, and precipitate withdrawal ex vivo by exposing the brain slice to naloxone. We expect to find an increase of GABA release from FSIs onto D2-MSNs during withdrawal, a neuroplastic change that would explain why FSIs constrain aversion during withdrawal. We will also measure the trajectory of cellular changes after repeated withdrawals in vivo, and predict the cyclical engagement of FSIs and MSNs during each withdrawal episode will generate enduring and maladaptive neuroplasticity in the nucleus accumbens. Successful completion of these experiments will uncover a novel role for nucleus accumbens FSIs in opioid effects, and indicate these cells represent a new therapeutic target for alleviating states of opioid withdrawal.