MIXED NOP/MU COMPOUNDS AND THE INVOLVEMENT OF THEIR RECEPTORS IN ANALGESIA

混合 NOP/MU 化合物及其受体在镇痛中的作用

• 批准号: 9980820
• 负责人: LAWRENCE R TOLL
• 金额: $ 45.29万
• 依托单位: FLORIDA ATLANTIC UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9980820
• 关键词: Absence of pain sensation; Acute; Acute Pain; Affective; Afferent Neurons; Agonist; Analgesics; Anatomy; Animals; Anterior; Attenuated; Back; Behavior; Behavioral; Brain; Brain region; C-terminal; Cells; Chimeric Proteins; Chronic; Coupled; Crystallization; Development; Dimerization; Down-Regulation; Drug abuse; Emotional; Family; Fc Receptor; Gender; Grant; Green Fluorescent Proteins; Histocytochemistry; Hyperalgesia; Injections; Investigation; Knock-in Mouse; Laboratories; Ligands; Location; Mechanics; Mediating; Messenger RNA; Methods; Microinjections; Modality; Mus; Neurons; Neuropathy; Nociception; Opioid; Opioid Analgesics; Opioid Receptor; Pain; Pathway interactions; Peripheral; Pharmaceutical Preparations; Pharmacology; Property; Receptor Activation; Receptor Down-Regulation; Research; Role; Sensory; Skin; Spinal; Spinal Cord; Spinal Ganglia; Spinal nerve structure; Structure; System; Tactile; Testing; Thalamic structure; Touch sensation; allodynia; animal pain; brain pathway; chronic neuropathic pain; chronic pain; chronic painful condition; cingulate cortex; delta receptors; enhanced green fluorescent protein; experimental study; inflammatory pain; member; mu opioid receptors; mu receptors; neural circuit; novel; pain processing; painful neuropathy; postsynaptic; prevent; protein expression; protein kinase C gamma; receptor; receptor function; response; sensory system; small molecule; somatosensory; tool

The NOP receptor, the fourth member of the opioid receptor family, has been the target of investigation since its discovery in 1993, with respect to pharmacology, anatomy, and behaviors elicited by agonists and antagonists. Despite considerable research efforts, the lack of suitable receptor antibodies has prevented the appropriate interpretation of many studies pertaining to the details of receptor location, internalization, and dimerization. In order to test hypotheses pertaining to NOP receptor function, Dr. Brigitte Kieffer and colleagues have generated knock-in mice that carry green fluorescent protein (eGFP) coupled to the NOP receptor. Similar GFP-tagged delta receptor and mCherry-tagged mu receptor knock-in mice have proven very useful in understanding the relationship among anatomy, cellular localization, and function of delta and mu opioid receptors. Like the mu receptor, NOP receptors are found in very high numbers in all of the pain-related brain regions, including PAG, RVM, MHb, thalamus, etc. However, NOP receptors are unlike the other members of the opiate receptor family in that NOP receptor agonists block opiate analgesia when administered i.c.v. while having antinociceptive activity when administered intrathecally. In addition, NOP receptor agonists appear to be more effective rather than less effective in chronic pain states. This is surprising since NOP receptor mRNA decreases in DRG and anterior cingulate cortex (ACC) and NOP receptors decrease in certain spinal cord laminae in spinal nerve ligated mice. Using NOP-eGFP(+/+) mice, immunohistochemical experiments will be carried out to better understand the circuitry and the cellular localization in brain, spinal cord, and DRG that leads to these unusual properties of N/OFQ and other NOP receptor agonists. These will be correlated with behavioral experiments subsequent to microinjections into specific brain regions to understand how NOP receptor activation modulates the sensory as well as the affective component of pain. Specific Aim 1 will carefully examine the location of NOP-eGFP receptors in DRG as well as determine the pain modalities (heat, cold, touch) attenuated by systemic administration of NOP agonists and antagonists and determine how these parameters change during chronic neuropathic and inflammatory pain. Specific Aim 2 will examine spinal cord NOP-eGFP expression as well as characterize spinal projections both to the brain and to the periphery. These results will be compared with the effects of NOP agonists on different pain modalities after intrathecal administration in sham and neuropathic mice. Specific Aim 3 will examine neuropathic pain-induced changes in NOP-eGFP receptor levels in brain with particular emphasis on regions involved in the sensory (PAG) and affective (ACC) components of pain. Direct injections of NOP receptor agonists and antagonists into these brain regions will be used to better understand the NOP receptor-related circuitry that modulates thermal, tactile, and emotional pain through these brain regions. These experiments will clearly identify the role of NOP receptors in acute and chronic thermal and tactile pain, allodynia and hyperalgesia.

NOP受体是阿片受体家族的第四个成员，一直是研究的目标 自 1993 年发现以来，在药理学、解剖学和激动剂引起的行为方面， 对手。尽管进行了大量的研究工作，但缺乏合适的受体抗体阻碍了 对许多有关受体位置、内化和受体细节的研究进行了适当的解释 二聚化。为了检验有关 NOP 受体功能的假设，Brigitte Kieffer 博士和 同事们已经培育出携带与 NOP 偶联的绿色荧光蛋白 (eGFP) 的敲入小鼠 受体。类似的 GFP 标记的 delta 受体和 mCherry 标记的 mu 受体敲入小鼠已被证明非常有效 有助于理解 delta 和 mu 的解剖学、细胞定位以及功能之间的关系 阿片受体。与 mu 受体一样，NOP 受体在所有与疼痛相关的疾病中也存在大量存在。 大脑区域，包括 PAG、RVM、MHb、丘脑等。然而，NOP 受体与其他受体不同 阿片受体家族成员，NOP 受体激动剂在给药时可阻断阿片镇痛 静脉注射同时鞘内给药时具有抗伤害活性。此外，NOP受体激动剂 在慢性疼痛状态下似乎更有效而不是更无效。这是令人惊讶的，因为 NOP DRG 和前扣带皮层 (ACC) 受体 mRNA 减少，某些区域 NOP 受体减少 脊髓神经结扎小鼠的脊髓层。使用NOP-eGFP(+/+)小鼠，进行免疫组化实验 将进行以更好地了解大脑、脊髓和 DRG 中的电路和细胞定位 这导致了 N/OFQ 和其他 NOP 受体激动剂的这些不寻常的特性。这些将是相关的 在特定大脑区域进行显微注射后进行行为实验，以了解 NOP 受体激活调节疼痛的感觉和情感成分。具体目标 1 将 仔细检查 DRG 中 NOP-eGFP 受体的位置，并确定疼痛方式（热、 通过全身施用 NOP 激动剂和拮抗剂来减弱冷、触摸），并确定这些如何 慢性神经性疼痛和炎症性疼痛期间参数会发生变化。具体目标 2 将检查脊髓 NOP-eGFP 表达以及表征到大脑和外周的脊柱投射。 这些结果将与 NOP 激动剂对鞘内注射后不同疼痛方式的效果进行比较 在假小鼠和神经病小鼠中给药。具体目标 3 将检查神经性疼痛引起的变化 大脑中 NOP-eGFP 受体水平，特别强调涉及感觉 (PAG) 的区域和 疼痛的情感（ACC）成分。将 NOP 受体激动剂和拮抗剂直接注射到这些 大脑区域将用于更好地了解调节热、 通过这些大脑区域产生触觉和情感疼痛。这些实验将清楚地确定 NOP 的作用 急性和慢性热痛和触觉痛、异常性疼痛和痛觉过敏的受体。