Physiological Implications of Opioid Receptor Regulation

阿片受体调节的生理意义

• 批准号: 7873147
• 负责人: Laura M. Bohn
• 金额: $ 6.54万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 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 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7873147
• 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，但在临床上受到多种不良特性的限制，包括耐受性、依赖性和呼吸抑制的发生。阿片类镇痛药，例如吗啡，主要通过激活 mu 阿片受体 (muOR) 来介导其生物效应。 muOR 是一种 G 蛋白偶联受体 (GPCR)，在称为受体脱敏的过程中受到 GPCR 激酶 (GRK) 磷酸化和随后的 betaarrestins 结合的调节。小鼠体内 βarrestin2 (betaarr2) 的基因消除似乎产生了矛盾的效果。它会增强和延长吗啡镇痛作用，并显着降低吗啡耐受性。此外，这些小鼠的身体依赖性没有表现出任何变化；相反，呼吸抑制实际上被消除了。吗啡在该小鼠模型中的作用接近临床使用的假设的最佳阿片类镇痛药。在 betaarr2 敲除 (betaarr2-KO) 小鼠中与吗啡镇痛相关的大脑区域中 muOR 与 G 蛋白的偶联升高，这可能有助于增强镇痛反应。然而，betaarr2 在吗啡诱导的呼吸抑制中的作用尚不清楚。此外，虽然吗啡镇痛作用在 betaarr2-KO 小鼠中得到增强，但对芬太尼和美沙酮等其他阿片类药物的反应没有改变。我们假设 GRK 和 betaarrestins 调节 muOR，并且这种调节的特异性由船上的阿片激动剂决定。 muOR 水平上的这些调节差异可能是多种临床相关阿片类药物（例如吗啡、芬太尼、美沙酮和丁丙诺啡）产生不同药理作用的基础。我们有独特的机会通过研究缺乏单个 GRK（GRK2、GRK3、GRK4、GRK5 和 GRK6）或 betarr2 的小鼠品系中阿片介导的行为和生理反应来评估 GRK 和 betarr2 对体内阿片反应的贡献。将在行为研究的同时评估这些相同动物的神经化学改变，重点是受体运输、受体脱敏和下游神经适应性变化。 HEK-293 细胞将用作模型系统，以进一步阐明观察到的体内现象背后的分子机制。本研究的总体目标是更好地了解 muOR 调节，以确定药物对生理和病理条件的特异性。为了实现这一目标，这些研究重点考察 GRK 和 parrestins 对 muOR 调节在阿片耐受性 (AIM I)、依赖性 (AIM II) 和阿片引起的副作用 (AIM III) 发展过程中的贡献。阐明 muOR 调节的复杂性可能会指向微调受体反应性，以提高镇痛功效、限制滥用倾向并消除开发阿片类药物疗法的不良副作用。

项目成果

Seeking Ligand Bias: Assessing GPCR Coupling to Beta-Arrestins for Drug Discovery.

寻求配体偏差：评估 GPCR 与 Beta-Arrestins 的偶联以进行药物发现。

• 发表时间: 2010
• 作者: Bohn, Laura M;McDonald, Patricia H
• 通讯作者: McDonald, Patricia H