Neuropeptidergic Inhibition of Spinal Pain Transmission

神经肽能抑制脊髓疼痛的传播

• 批准号: 10063565
• 负责人: BRADLEY K. TAYLOR
• 金额: $ 45.13万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-10 至 2021-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10063565
• 关键词: AMPA Receptors; Absence of pain sensation; Action Potentials; Acute; Address; Adenylate Cyclase; Affect; Afferent Neurons; Agonist; American; Analgesics; Biological Assay; Books; Chronic; Chronic inflammatory pain; Confocal Microscopy; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data; Disease remission; Electric Stimulation; Electrophysiology (science); Evoked Potentials; Failure; Fiber; Frequencies; Funding; Fura-2; Genetic; Goals; Hyperalgesia; Image; Immunohistochemistry; In Situ; Inflammation; Injury; Interneurons; Intrathecal Injections; Label; Lasers; Left; Mediating; Methods; Molecular; Mus; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; Neurons; Neuropeptide Y Receptor; Neurotoxins; Nociceptors; Pain; Peripheral nerve injury; Persistent pain; Pharmacology; Physical Function; Physiologic pulse; Posterior Horn Cells; Productivity; Proteins; Public Health; Publishing; Quality of life; Receptor Activation; Receptor Signaling; Reporting; Research; Signal Transduction; Site; Slice; Spinal; Spinal Cord; Spine pain; Stimulus; Synapses; TRPV1 gene; Testing; Traumatic injury; Work; central sensitization; chronic pain; cost; dorsal horn; excitatory neuron; in vivo; inhibitor/antagonist; knock-down; mental function; nerve injury; neuropeptide Y; neuropeptide Y-Y1 receptor; novel; pain chronification; pain relief; painful neuropathy; patch clamp; prevent; public health relevance; receptor; receptor internalization; response; small molecule inhibitor; somatosensory; spinal nerve posterior root; synaptic inhibition; tissue injury; transmission process

Nerve injury dramatically increases NPY expression in sensory neurons and NPY receptor-mediated analgesia, yet this is underappreciated as a potential pain relief mechanism that might prevent the transition from acute to chronic pain. Among 35 original research articles, reviews, and a book published during the previous funding cycle (28 as first or senior authors), our work published in PNAS discovered that intrathecal NPY receptor antagonists or conditional genetic NPY depletion reinstated hyperalgesia, even when applied months after nerve injury or inflammation. Our overall hypothesis is that injury induces a sustained release of NPY and activation of NPY Y1 receptor signaling that opposes the transition to a chronic state of lasting pain vulnerability. However, whether tissue- or nerve-injury induced increases in spinal NPY Y1 receptor (Y1R) signaling is associated with a tonic increase in the releasable pool of NPY has been difficult to determine. To address this gap, we developed a new in situ assay of functional NPY release (Y1R internalization). Our new data indicate that Y1R internalization is greater with nerve injury after high frequency electrical stimulation of dorsal horn slices or after in vivo non-noxious stimulation of the hindpaw. Specific Aim 1 will use this novel method to test the hypothesis that non-noxious stimulus-evoked release of NPY from A-fibers will remain primed for weeks and even months after nerve injury. We now report that NPY produces an outward current and inhibits action potentials evoked by dorsal root stimulation (DRS) in Y1-EGFP labeled neurons. To test the hypothesis that injury increases synaptic inhibition by NPY, Specific Aim 2A will patch-clamp lamina II neurons and conduct Fura-2 [Ca2+]i imaging at peak of hyperalgesia after injury. We predict that Y1R agonists will inhibit stimulus-evoked responses and their concentration-response curves will be left-shifted by injury. Our progress with NPY saporin-conjugated neurotoxin indicates that Y1R-expressing dorsal horn neurons contribute to neuropathic pain, and new double-label immunohistochemistry and patch-clamp electrophysiology data in Y1R-EGFP mice support the concept that Y1R-positive neurons are excitatory. To test the hypothesis that Y1R-expressing neurons maintain LS after inflammation or nerve injury, but are held in check by NPY, Specific Aim 2B will evaluate the effects of Y1 receptor antagonists on [Ca2+]i mobilization and NMDA or AMPA receptor currents in Y1R-expressing neurons upon dorsal root stimulation or laser-directed NMDA/AMPA uncaging. Specific Aim 3 will then use an intrathecal pharmacology approach to determine whether NPY silences pronociceptive GluN AC1 Epac signaling on Y1R-expressing dorsal horn neurons and TRPA1 TRPV1 signaling on central afferents terminals. Completion of this project will bring us closer to our long-term goal of alleviating chronic pain by either: a) facilitating endogenous NPY analgesia, thus restricting pain within a state of remission; or b) extinguishing spinal neuron sensitization altogether, for example with a selective AC1 or Epac1 inhibitor.

神经损伤显着增加了感觉神经元和NPY受体介导的NPY表达 镇痛，但这被视为一种潜在的缓解疼痛机制，可能会阻止过渡 从急性到慢性疼痛。在35篇原始研究文章中，评论和一本在 以前的资金周期（28名作为第一或高级作者），我们在PNAS上发表的作品发现鞘内 NPY受体拮抗剂或有条件的遗传NPY部署恢复了Hypergeria，即使应用了 神经损伤或炎症几个月后。我们的总体假设是伤害导致持续释放 NPY和NPY Y1受体信号的激活反对过渡到持续疼痛的慢性状态 脆弱性。但是，组织 - 或神经伤害是否诱导脊柱NPY Y1受体（Y1R）的增加 信号传导与可释放的NPY库的补品增加有关。到 解决了这一差距，我们开发了对功能NPY释放（Y1R内部化）的新原位评估。我们的新 数据表明在高频电刺激后神经损伤的Y1R内在化更大 背角切片或体内无刺激后的后爪刺激。特定目标1将使用这本小说 测试假说，即从A纤维中脱离NPY释放的假设将保持 神经受伤后几周甚至几个月。我们现在报告说NPY产生了外在电流 并抑制Y1-EGFP标记为神经元的背根刺激（DRS）引起的动作电位。测试 假设损伤会增加NPY的突触抑制作用，特异性AIM 2A将贴上夹具板层II 神经元并在损伤后触及过敏的峰值上进行Fura-2 [Ca2+] I成像。我们预测Y1R激动剂 将抑制刺激诱发的反应，其浓度 - 响应曲线将被伤害左移。我们的 NPY糖蛋白结合的神经毒素的进展表明表达Y1R的背角神经元 有助于神经性疼痛以及新的双标签免疫组织化学和斑块钳 Y1R-EGFP小鼠中的电生理数据支持Y1R阳性神经元是兴奋性的概念。到 检验以下假设，即表达Y1R的神经元在感染或神经损伤后保持LS 由NPY进行检查，具体AIM 2B将评估Y1受体拮抗剂对[Ca2+] I动员和 在背根刺激或激光导向后表达Y1R的神经元中的NMDA或AMPA受体电流 NMDA/AMPA衰老。然后，特定的目标3将使用鞘内药理学方法来确定 npy沉默是否引起him grunAC1-表达Y1R的背角神经元上的EPAC信号传导 和TRPA1TRPV1信号传导在中央传入端子上。该项目的完成将使我们更接近 我们通过任何一种减轻慢性疼痛的长期目标：a）促进内源性npy镇痛，因此 限制缓解状态内的疼痛；或b）完全熄灭脊髓神经敏化 具有选择性AC1或EPAC1抑制剂的示例。