Mu opioid receptor function in the enteric nervous system

Mu阿片受体在肠神经系统中的功能

• 批准号: 8011605
• 负责人: CATIA STERNINI
• 金额: $ 10万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-15 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8011605
• 关键词: Abdominal Pain; Acute; Adverse effects; Affect; Agonist; Analgesics; Arrestins; Cell Fractionation; Cells; Chronic; Clinical; Confocal Microscopy; Constipation; Cyclic AMP; Development; Dominant-Negative Mutation; Drug usage; Dynamin; Endocytosis; Enteral; Enteric Nervous System; Event; Fentanyl; G-Protein-Coupled Receptors; GTP-Binding Proteins; Guanosine Triphosphate Phosphohydrolases; Human; Immunohistochemistry; In Situ; In Vitro; Intestines; Knowledge; Ligands; Mediating; Mitogen-Activated Protein Kinase Inhibitor; Mitogen-Activated Protein Kinases; Morphine; Neurons; Opiates; Opioid; Opioid Receptor; Pain Threshold; Pain management; Patients; Pharmaceutical Preparations; Phosphorylation; Physiological Adaptation; Proteins; Receptor Activation; Receptor Mediated Signal Transduction; Receptor Signaling; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Pathway; Signal Transduction; Syndrome; Testing; Time; Transfection; Up-Regulation; Ventilatory Depression; Western Blotting; desensitization; endogenous opioids; ileum; in vivo; novel therapeutic intervention; prevent; receptor; receptor function; receptor internalization; response; trafficking

DESCRIPTION (provided by applicant): Ligand-induced trafficking of G protein-coupled receptors and their interaction with associated proteins are key steps regulating receptor-mediated signal transduction and cellular responsiveness. ? opioid receptor (?OR) mediates the analgesic effects of opiates, potent drugs used for pain control, and their side effects, including opioid bowel syndrome (profound constipation and abdominal pain), and tolerance. We previously showed that a) ?OR endocytoses in enteric neurons in response to endogenously opioids and to most opiates, but not to morphine, b) chronic ?OR activation confers morphine the ability to trigger ?OR endocytosis and induces over expression and translocation of dynamin, an intracellular protein that is important for receptor internalization, c) the magnitude of ?OR endocytosis induced by high efficacy opiates does not change in a condition of opioid tolerance, d) activation of ?OR with an internalizing agonist stimulates mitogen-activated protein kinase (MAPK) phosphorylation in cultured myenteric neurons. This application will test the hypothesis that prolonged ?OR activation induces alterations in the intracellular machinery that regulates agonist-induced ?OR trafficking and post-receptor signaling in enteric neurons, which are possible mechanisms underlying the development of tolerance. Specific Aim 1 will establish which intracellular proteins regulate ?OR trafficking following acute and chronic activation in vitro using neuronal transfection of native cells expressing ?OR and correlate their expression with receptor endocytosis and state of gut tolerance in vivo. Specific Aim 2 will determine the effects of acute and chronic ?OR stimulation on MAPK activation in enteric neurons, the effects of MAPK inhibitors on agonist- induced ?OR desensitization and internalization, and whether chronic opiate treatment resulting in a state of tolerance in the gut induces sustained MAPK activation in intact segments of the ileum. These studies will provide a better knowledge of opiate-induced adaptations in enteric neurons naturally expressing ?OR, which will increase our understanding of opioid bowel syndrome, a condition affecting patients receiving chronic opiates for pain, and tolerance, which hamper the use of these drugs.

描述（由申请人提供）：配体诱导的 G 蛋白偶联受体的运输及其与相关蛋白的相互作用是调节受体介导的信号转导和细胞反应性的关键步骤。 ？阿片受体 (?OR) 介导阿片类药物（用于控制疼痛的强效药物）的镇痛作用及其副作用，包括阿片类肠道综合征（严重便秘和腹痛）和耐受性。我们之前表明，a) 肠道神经元中的 ?OR 内吞作用响应于内源性阿片类药物和大多数阿片类药物，但不是吗啡，b) 慢性 ?OR 激活赋予吗啡触发 ?OR 内吞作用的能力，并诱导动力蛋白（一种对受体内化很重要的细胞内蛋白）过度表达和易位，c) 高效诱导的 ?OR 内吞作用的程度 阿片类药物在阿片类药物耐受的情况下不会改变，d)用内化激动剂激活？OR会刺激培养的肌间神经元中的丝裂原激活蛋白激酶（MAPK）磷酸化。该应用将测试以下假设：延长的 ?OR 激活会诱导细胞内机制的改变，调节激动剂诱导的 ?OR 运输和肠神经元中的受体后信号传导，这是耐受性发展的可能机制。具体目标 1 将通过表达 ?OR 的天然细胞的神经元转染，确定哪些细胞内蛋白在体外急性和慢性激活后调节 ?OR 运输，并将其表达与受体内吞作用和体内肠道耐受状态相关联。具体目标 2 将确定急性和慢性 ?OR 刺激对肠神经元 MAPK 激活的影响、MAPK 抑制剂对激动剂诱导的 ?OR 脱敏和内化的影响，以及导致肠道耐受状态的慢性阿片治疗是否会在回肠完整段中诱导持续的 MAPK 激活。这些研究将更好地了解阿片类药物诱导的自然表达 ?OR 的肠神经元的适应，这将增加我们对阿片类肠综合征的了解，阿片类药物肠综合征是一种影响因疼痛和耐受而接受长期阿片类药物治疗的患者的疾病，而这阻碍了这些药物的使用。