Physiological Implications of Opioid Receptor Regulation

阿片受体调节的生理意义

• 批准号: 7269927
• 负责人: Laura M. Bohn
• 金额: $ 24.81万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7269927
• 关键词: ADRBK1 gene; ADRBK2 gene; Ablation; Absence of pain sensation; Acute; Address; Adverse effects; Aftercare; Agonist; Analgesics; Animals; Arr2; Arrestin; Arrestins; Behavior; Behavioral; Binding; Biological; Biological Models; Brain region; Buprenorphine; CREB1 gene; Cells; Chronic; Clathrin; Clinical; Complement; Condition; Coupling; Cultured Cells; Dependence; Development; Drug effect disorder; Equilibrium; Fentanyl; G Protein-Coupled Receptor Genes; G protein coupled receptor kinase; G-Protein-Coupled Receptors; GRK4 gene; GRK5 gene; GRK6 gene; GTP-Binding Proteins; Gastrointestinal Transit; Genetic; Goals; Gold; Human; Immersion Investigative Technique; In Vitro; Individual; Light; Maps; Measures; Mediating; Methadone; Molecular; Molecular Models; Monitor; Morphine; Mouse Strains; Mus; Mutant Strains Mice; Narcotics; Numbers; Opiate Addiction; Opiates; Opioid Peptide; Opioid Receptor; Pain; Peripheral; Pharmaceutical Preparations; Pharmacologic Substance; Phosphorylation; Phosphotransferases; Physical Dependence; Physiological; Physiology; Play; Process; Property; Range; Receptor Activation; Regulation; Regulatory Element; Research Personnel; Respiration; Respiratory physiology; Role; Signal Transduction; Site; Specificity; Standards of Weights and Measures; Tail; Testing; Time; Transcription Factor AP-2 Alpha; Water; Wild Type Mouse; Withdrawal; behavior test; brain tissue; clinically relevant; desensitization; design; gastrointestinal function; ilium; in vivo; intracellular protein transport; mouse model; mu opioid receptors; mutant; neurochemistry; programs; protein transport; receptor; receptor function; respiratory; response; trafficking

DESCRIPTION (provided by applicant): Morphine, the gold standard for pain relief, is clinically limited by several adverse properties including tolerance, dependence and the onset of respiratory suppression. Opiate analgesics, such as morphine, mediate their biological effects mainly via activation of the mu opioid receptor (muOR). The muOR, a G protein coupled receptor (GPCR), is regulated by GPCR kinase (GRK) phosphorylation and subsequent binding of betaarrestins in a process known as receptor desensitization. The genetic ablation of betaarrestin2 (betaarr2)in mice has seemingly paradoxical effects; it leads to enhanced and prolonged morphine analgesia and dramatically reduces morphine tolerance. Moreover, these mice display no change in physical dependence; in contrast, respiratory suppression is practically eliminated. The effects of morphine in this mouse model approach a hypothetical, optimal opiate analgesic for clinical use. The coupling of the muOR to G proteins is elevated in brain regions associated with morphine analgesia in the betaarr2knockout (betaarr2-KO) mice which may contribute to the enhanced analgesic responses. However, the role of betaarr2 in morphine-induced respiratory suppression is unclear. Furthermore, while morphine analgesia is enhanced in the betaarr2-KO mice, lresponses to other opiates such as fentany and methadone, are unaltered. We have hypothesized that GRKs and betaarrestins regulate muORs and the specificity of this regulation is determined by the opiate agonist onboard. These regulatory differences at the level of the muOR may thereby underlie the diverse pharmacological effects produced by a wide-range of clinically relevant opiates such as morphine, fentanyl, methadone and buprenorphine. We have the unique opportunity to evaluate the contributions of GRKs and betarr2 to opiate responses in vivo by studying opiatemediated behaviors and physiological responses in strains of mice lacking individual GRKs (GRK2, GRK3, GRK4, GRK5, and GRK6) or betarr2. Neurochemical alterations will be assessed in these same animals in parallel to the behavioral studies with a focus on receptor trafficking, receptor desensitization, and downstream neuroadaptive changes. HEK-293 cells wil be used as a model system to further elucidate the molecular mechanisms underlying the observed in vivo phenomena. The overall objective of this study is to gain a greater understanding of muOR regulation in determining the specificity of drug effects on physiological and pathological conditions. Toward this goal, these studies focus on examining the contribution of GRKs and parrestins to muOR regulation in the development of opiate tolerance (AIM I), dependence (AIM II), and the side effects induced by opiates (AIM III). Illuminating the intricacies of muOR regulation may point to fine-tuning receptor responsiveness to increase analgesic efficacy, limit abuse liabilityand eliminate adverse side effects in developing opiate pharmaceutical therapies.

描述（由申请人提供）：吗啡是缓解疼痛的黄金标准，在临床上受到多种不良特性，包括公差，依赖性和呼吸抑制的发作。阿片类镇痛药，例如吗啡，主要通过激活MU阿片受体（MUOR）介导其生物学作用。 MUOR是G蛋白偶联受体（GPCR），受到GPCR激酶（GRK）磷酸化的调节，然后在称为受体脱敏的过程中βArrestins的随后结合。小鼠中betaarrestin2（betaarr2）的遗传消融似乎具有自相矛盾的作用。它导致增强和延长吗啡镇痛，并大大降低吗啡的耐受性。此外，这些小鼠的身体依赖性没有变化。相反，实际上消除了呼吸抑制。吗啡在这种小鼠模型中的作用方法是一种假设的，最佳的阿片类镇痛作用，用于临床使用。在betaarr2knockout（betaarr2-ko）小鼠中，在与吗啡镇痛相关的大脑区域中，MUOR与G蛋白的耦合升高，这可能有助于增强的镇痛反应。然而，贝塔尔2在吗啡诱导的呼吸抑制中的作用尚不清楚。此外，虽然在betaarr2-ko小鼠中增强了吗啡镇痛，但诸如芬那坦和美沙酮等其他阿片类药物的量子却没有改变。我们假设Grks和betaarrestin调节了MUORS，并且该调节的特异性由鸦片激动剂机上确定。这些调节性差异在MUOR水平上可能是由大量临床相关的阿片类药物（例如吗啡，芬太尼，美沙酮和丁丙诺啡）产生的多种药理作用的基础。我们有独特的机会来评估GRK和BETARR2通过研究缺乏单个GRK（GRK2，GRK3，GRK4，GRK5和GRK6）或BETARR2的小鼠菌株中的阿片相关行为和生理反应来评估体内反应的贡献。在这些相同动物的行为研究中，将评估神经化学改变，重点是受体运输，受体脱敏和下游神经适应性变化。 HEK-293细胞将被用作模型系统，以进一步阐明观察到的体内现象所观察到的分子机制。这项研究的总体目的是在确定药物对生理和病理状况的影响的特异性方面对MUOR调节有更多的了解。为了实现这一目标，这些研究着重于研究GRK和帕林斯蛋白对鸦片耐受性发展（AIM I），依赖性（AIM II）和阿片类药片引起的副作用（AIM III）的贡献。照亮MUOR调节的复杂性可能表明受体反应性以提高镇痛功效，限制滥用责任，并消除开发鸦片制药疗法的不利副作用。