Heroin withdrawal: modulation of aversive states by kappa opioid receptors

描述(申请人提供)：海洛因成瘾是一种慢性复吸障碍，与严重的社会经济和公共健康后果有关。海洛因成瘾者在停止使用毒品时会出现严重的烦躁不安和厌恶的戒断症状。这些负面反应是促使许多人复发的关键因素，即使在长期禁欲之后也是如此。关于戒断后这些反应的神经生物学基础，或者这种神经生物学如何导致个体复发的可能性，人们知之甚少。现有证据表明，kappa-阿片受体系统在厌恶、烦躁和抑郁状态中起着关键作用。拟议的实验旨在检查kappa-阿片受体在多大程度上驱动海洛因戒断期间出现的负面情感和与奖励相关的状态，尽管戒除，并激发复发。这些实验还将确定kappa-阿片受体是否有助于个人复发的易感性。这项提案的以下目标将使用一种临床相关的海洛因成瘾模型来解决这些问题，在该模型中，大鼠长期暴露于不断增加的海洛因剂量。目标1将测量kappa-阿片受体在戒断后阶段的分布和信号功能。这些发现将提供与海洛因戒断相关的持续性神经生物学变化的性质的重要细节。目标2将确定这些kappa-阿片受体变化的程度是否与海洛因偏好和/或戒断相关症状的大小相对应。这些发现将确定导致个人复发可能性的潜在行为和/或神经生物学风险因素。目标3将确定这些行为反应在多大程度上是由大脑关键动机和情感通路中的kappa-阿片受体介导的。一项使用小干扰RNA的创新技术将被用来减少腹侧被盖区神经元上kappa-阿片受体的表达。由于siRNAs具有显著的治疗潜力，这些发现将为开发长期治疗药物成瘾和防止复发的临床干预措施提供信息。总之，这些拟议的研究将扩大我们对kappa-阿片受体在海洛因依赖者中如何发挥作用的理解，以及这些受体如何导致以戒断后阶段为特征的烦躁和厌恶状态。这项研究还将深入了解kappa介导的个人对成瘾药物易感性的潜在机制，这是制定长期预防复发的个性化方法的重要一步。最终，这项研究将拓宽我们对内源性阿片受体系统如何被调节为成瘾治疗方法的理解。

DESCRIPTION (provided by applicant): Heroin addiction is a chronic relapsing disorder associated with significant socioeconomic and public health consequences. Heroin addicts experience severe dysphoria and aversive withdrawal symptoms when drug use is discontinued. These negative responses are crucial factors that motivate relapse in many individuals, even after extended periods of abstinence. Little is known about the neurobiological basis of these responses across the post-withdrawal period, or how this neurobiology contributes to an individual's likelihood of relapse. Existing evidence suggests that the kappa-opioid receptor system plays a key role in states of aversion, dysphoria and depression. The proposed experiments aim to examine the extent to which kappa-opioid receptors drive the negative affective and reward-related states that emerge during heroin withdrawal, persist despite abstinence, and motivate relapse. These experiments will also identify whether kappa-opioid receptors contribute to an individual's vulnerability to relapse. The following Aims of this proposal will use a clinically relevant model of heroin addiction, in which rats are chronically exposed to escalating doses of heroin, to address these questions. Aim 1 will measure the distribution and signaling function of kappa-opioid receptors across the post- withdrawal period. These findings will provide important details about the nature of the persistent neurobiological changes associated with heroin withdrawal. Aim 2 will identify if the degree of these kappa- opioid receptor changes corresponds to the magnitude of heroin preference and/or withdrawal-related symptoms expressed by individual rats across the post-withdrawal period. These findings will identify potential behavioral and/or neurobiological risk factors contributing to an individual's likelihood of relapse. Aim 3 will determine the extent to which these behavioral responses are mediated by kappa-opioid receptors within critical motivation and affective pathways of the brain. An innovative technique using small interfering RNAs will be used to reduce the expression of kappa-opioid receptors on neurons in the ventral tegmental area. As siRNAs have significant therapeutic potential, these findings will inform the development of clinical interventions for the long-term treatment of drug addiction and prevention of relapse. Together, these proposed studies will extend our understanding of how kappa-opioid receptors function in heroin-dependent individuals, and how these receptors contribute to the dysphoria and aversive states that characterize the post-withdrawal period. This research will also provide insight into potential kappa-mediated mechanisms of individual vulnerability to addictive drugs, which represents an important step in the development of personalized approaches to the long-term prevention of relapse. Ultimately, this research will broaden our understanding of how endogenous opioid-receptor systems may be modulated as an approach to addiction therapy.