Signaling balance and opioid dependence

信号平衡和阿片类药物依赖

基本信息

批准号：
10503891
负责人：
JENNIFER L WHISTLER
金额：
$ 66.36万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-30 至 2027-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10503891
关键词：
Abstinence Acute Agonist Analgesics Animals Arrestins Behavior Behavioral Biology Brain Cells Characteristics Clinical Cognitive Color Data Decision Making Dependence Diagnosis Distress Dopamine Dopamine D2 Receptor Down-Regulation Drug Exposure Drug Modelings Drug abuse Endocytosis Endorphins Engineering Enkephalins Equilibrium Essential Drugs Exposure to Failure G-Protein-Coupled Receptors GABA Receptor GTP-Binding Proteins Genotype Goals Human Impairment Knock-in Mouse Lateral Ligands Link Medial Modeling Molecular Monitor Morphine Morphine Dependence Mus Naloxone Neurons Nucleus Accumbens Opiate Addiction Opioid Pain Pathologic Pathology Patients Pharmaceutical Preparations Pharmacology Phenotype Physical Dependence Positioning Attribute Pre-Clinical Model Prefrontal Cortex Probability Property Recycling Regimen Relapse Research Rewards Risk Role Self Administration Signal Transduction Signaling Protein Study models Substance Use Disorder Synapses Time Ventral Tegmental Area Weaning Wild Type Mouse Withdrawal Work addiction base dopaminergic neuron drug abstinence drug withdrawal experimental study flexibility gamma-Aminobutyric Acid mu opioid receptors mutant neuroadaptation neuromechanism novel opioid abuse opioid epidemic opioid use pain relief pre-clinical research preclinical study prevent protein activation receptor recruit relating to nervous system response sensor side effect tool

项目摘要

Opioid drugs are essential medications for the relief of serious pain, with no substitutes currently available for postsurgical and other severe indications. Long term use of opioids, however, leads to numerous side effects, and to substantial risk of substance use disorder (SUD). SUD or “addiction” is diagnosed based on behavioral characteristics that manifest broadly as loss of control or “compulsive” drug seeking and impaired decision making or “cognitive flexibility” even after months to years of abstinence. However, the majority of preclinical research of drug abuse focuses on models of drug-taking and reward-seeking rather than on the long-lasting changes in behavioral flexibility that underlie human SUDs. In addition, preclinical studies of SUD mechanism have been limited to comparing animals that have or have not taken drug. This has made it difficult to dissociate opioid- induced changes in biology and behavior that occur merely due to drug exposure from those that actually underlie the pathology of a SUD. We have developed a unique tool to circumvent this significant confound in opioid abuse research. Specifically, we have developed a knock-in mouse that expresses a modified mu opioid receptor (MOR) with altered signaling properties. The MOR when activated by its endogenous ligands, endorphins and enkephalins, engages G protein signaling to control neuronal activity. Following G protein activation by endogenous ligand, most G protein coupled receptors (GPCR), including the MOR, then rapidly recruit arrestins that silence the G protein signal and promote receptor endocytosis and, for the MOR, rapid recycling. This mechanism thereby carefully titrates G protein signal with a precision and time course ideally suited to respond to transmitters that are released in a pulsatile manner. In contrast, MORs activated by morphine and all its derivates effectively engage G protein signaling but poorly engage arrestins. In the current vernacular of GPCR pharmacology, morphine is termed a “biased” agonist, signaling preferentially to G protein over arrestins while endorphins are “balanced” agonists, engaging both G proteins and arrestins. The RMOR receptor was engineered to effectively engage both G protein and arrestin when activated by morphine without altering signaling in response to endogenous transmitters. Importantly, in our extensive previous work, we have found that RMOR mice do not develop tolerance or dependence to morphine nor do they transition to compulsive drug seeking in a model of SUD under conditions where wild type (WT) mice do. More recently, we have found while morphine causes long-lasting changes in cognitive flexibility in WT mice, this effect is also absent in RMOR mice. Here we will use WT and RMOR mice to pinpoint molecular and synaptic mechanisms that underlie SUDs in a paradigm where all mice receive drug but only WT show pathologic morphine responses. We propose that any morphine-induced changes that occur in both genotypes is likely to reflect a response to drug exposure, whereas changes confined to WT mice likely contribute to the pathology of SUDs.

阿片类药物是缓解严重疼痛的基本药物，目前尚无替代品然而，术后和其他严重的适应症长期使用阿片类药物会导致许多副作用。根据行为诊断出物质使用障碍 (SUD) 或“成瘾”的重大风险。广泛表现为失去控制或“强迫性”寻求药物以及决策受损的特征或“认知灵活性”，即使在禁欲数月至数年之后。然而，大多数临床前研究。药物滥用的研究重点是吸毒和寻求回报的模式，而不是长期的变化人类 SUD 的行为灵活性此外，SUD 机制的临床前研究也已开展。仅限于比较服用或未服用药物的动物，这使得分离阿片类药物变得困难。引起生物学和行为的变化，这些变化仅仅是由于实际潜在的药物暴露而发生的我们开发了一种独特的工具来规避阿片类药物滥用中的这一重大混乱。具体来说，我们开发了一种表达修饰的 mu 阿片受体的敲入小鼠。 (MOR) 被其内源性配体、内啡肽和内啡肽激活时，信号特性发生改变。脑啡肽通过 G 蛋白信号传导来控制神经元活动。内源配体，大多数 G 蛋白偶联受体 (GPCR)，包括 MOR，然后快速招募抑制蛋白沉默 G 蛋白信号并促进受体内吞作用，并且对于 MOR 来说，可以快速回收。机制仔细滴定 G 蛋白信号，其精确度和时间过程非常适合从而做出反应相比之下，MOR 是由吗啡及其所有物质激活的。在目前的 GPCR 术语中，衍生物可以有效地参与 G 蛋白信号传导，但不能很好地参与抑制蛋白。药理学中，吗啡被称为“偏向”激动剂，与抑制蛋白相比，优先向 G 蛋白发出信号，而内啡肽是“平衡”激动剂，与 G 蛋白和 RMOR 受体结合。被设计为在被吗啡激活时有效地结合 G 蛋白和视紫红质抑制蛋白，而不改变重要的是，在我们之前的大量工作中，我们发现了响应内源性递质的信号。 RMOR 小鼠不会对吗啡产生耐受性或依赖性，也不会转变为强迫性药物最近，我们发现在野生型（WT）小鼠的条件下寻找 SUD 模型。吗啡会导致 WT 小鼠认知灵活性发生持久变化，而 RMOR 小鼠也不存在这种效应。在这里，我们将使用 WT 和 RMOR 小鼠来查明 SUD 背后的分子和突触机制。所有小鼠接受药物但仅 WT 表现出病理性吗啡反应的范例我们建议任何。两种基因型中发生的吗啡诱导的变化可能反映了对药物暴露的反应，而仅限于 WT 小鼠的变化可能导致 SUD 的病理学。