Latent Sensitization and Neuropathic Pain

潜在致敏和神经性疼痛

• 批准号: 9355478
• 负责人: Juan Carlos Garcia Marvizon
• 金额: --
• 依托单位: VA GREATER LOS ANGELES HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-11-01 至 2019-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9355478
• 关键词: Adenylate Cyclase; Adrenergic Receptor; Affect; Afferent Neurons; Aging; Animals; Attention; Calcium; Calcium Channel; Characteristics; Corticotropin-Releasing Hormone; Cyclic AMP-Dependent Protein Kinases; Diabetes Mellitus; Disease; Disease remission; Esthesia; Feedback; General Population; Genes; Goals; Human; Hyperalgesia; Hypersensitivity; Image; Incidence; Inflammation; Inflammatory; Injury; Knockout Mice; Lead; Lesion; Measures; Mediating; Modeling; Molecular; Molecular Target; Mus; N-Methyl-D-Aspartate Receptors; NMDA receptor antagonist; Narcotic Antagonists; Nature; Nerve; Neural Pathways; Neuraxis; Neurons; Neuropathy; Nociception; Normalcy; Operative Surgical Procedures; Opiates; Opioid; Opioid Peptide; Opioid Receptor; Outcome; Pain; Pain Disorder; Pain-Free; Pathway interactions; Patients; Pharmaceutical Preparations; Phase; Phosphorylation; Population; Posterior Horn Cells; Pro-Opiomelanocortin; Rattus; Research; Rodent Model; Role; Services; Signal Pathway; Skin; Spinal Cord; Stimulus; Stress; Surgical incisions; Testing; Transgenic Mice; United States; Veterans; Western Blotting; Work; chronic pain; combat; dorsal horn; inhibitor/antagonist; interdisciplinary approach; nerve injury; painful neuropathy; palliative; patch clamp; prodynorphin; proenkephalin; receptor; receptor internalization; response; spared nerve; spontaneous pain; voltage

Veterans are particularly susceptible to neuropathic pain originating from combat wounds, surgery and diabetes. The long-term goal of this project is to find a cure for neuropathic pain that represents its true reversal and not just palliative measures. This goal can be achieved by investigating the molecular and cellular mechanisms of pain latent sensitization, a rodent model that reproduces key features of chronic pain disorders: indefinite duration and episodic presentation triggered by stress. Latent sensitization can occur following a variety of stimuli: inflammation, skin incision and nerve injuries that cause neuropathic pain. It is characterized by a period of hyperalgesia followed by a period of pain remission in which pain is generally absent but may reappear as pain episodes. This is due to the fact that the remission phase of latent sensitization does not represent a return to normality but an anomalous state in which pain is suppressed by a compensatory activation of opioid receptors. This is revealed by a return of pain (“reinstatement”) upon administration of opioid antagonists, which are without effect in normal animals or humans. The latent sensitization model emerged from the work of several research teams on opiate-induced hyperalgesia and its interaction with injury and stress. Only recently has the importance of latent sensitization as a model for chronic pain become clear, and there is only one study on its relevance for neuropathic pain. This project will investigate the mechanisms of latent sensitization in neuropathic pain. The Specific Aims are: 1) study the role of opioid receptors and stress in neuropathic latent sensitization; 2) determine whether the remission phase of latent sensitization is mediated by opioid release or by µ-opioid receptor constitutive activity; and 3) study the role of NMDARs and the adenylyl cyclase / protein kinase A pathway in neuropathic latent sensitization. We will test the following hypotheses: 1) µ-opioid receptors, κ-opioid receptors and α2A adrenergic receptors in the spinal cord mediate anti-hyperalgesia during the remission phase of nerve injury-induced latent sensitization; 2) µ-opioid receptors located in primary afferent terminals contribute to the remission phase of latent sensitization; 3) stress reinstates pain hyperalgesia during the remission phase of latent sensitization; 4) µ-opioid receptor constitutive activity, and not sustained opioid release, mediates pain remission; 5) pain sensitivity in latent sensitization is maintained by a positive feedback loop in which NMDARs and the adenylyl cyclase / protein kinase A pathway activate each other. This project will use a multidisciplinary approach to test these hypotheses. In Aim 1, a spared nerve injury model of neuropathic pain will be used in rats and mice to identify the receptors that suppress pain sensitivity in the remission phase. Using transgenic mice with selective deletion of µ-opioid receptors in nociceptive primary afferents, we will determine whether the µ-opioid receptors that suppress pain are located in primary afferents. We will also investigate how stress reinstates pain during the remission phase. In Aim 2, we will determine whether the anti-hyperalgesia produced by µ-opioid receptors is due to their constitutive activity by using patch-clamp recording from primary afferent neurons to measure their inhibition of voltage-gated calcium channels. The alternative hypothesis, that µ-opioid receptors are activated by sustained opioid release, will be tested using knock-out mice in the three genes that encode opioid peptides. In addition, opioid release will be measured as µ-opioid receptor internalization. In Aim 3, the interaction between NMDA receptors, adenylyl cyclase and protein kinase A during latent sensitization will be studied in primary afferent neurons using calcium imaging and patch-clamp. The activating phosphorylation of NMDA receptors by protein kinase A during latent sensitization will be measured with Western blots. Finally, NMDA receptor antagonists and inhibitors and activators of adenylyl cyclase and protein kinase A will be used to delineate the signal pathway that maintains latent sensitization. This will identify targets to develop medication to reverse neuropathic pain.

退伍军人特别容易受到战伤、手术和手术造成的神经性疼痛的影响。 该项目的长期目标是找到真正治疗神经性疼痛的方法。 逆转而不仅仅是姑息治疗措施可以通过研究分子和细胞来实现。 疼痛潜在敏化机制，一种重现慢性疼痛疾病关键特征的啮齿动物模型： 压力引发的不确定持续时间和间歇性表现可能发生在压力之后。 多种刺激：炎症、皮肤切口和神经损伤等引起神经性疼痛。 经过一段时间的痛觉过敏，然后是一段疼痛缓解期，其中疼痛通常不存在，但可能会 这是由于潜伏敏化的缓解阶段不会再次出现。 恢复正常但处于一种异常状态，其中疼痛被代偿性抑制 阿片受体的激活通过给药后疼痛的恢复（“恢复”）来揭示。 阿片类拮抗剂，对正常动物或人类没有作用。 来自多个研究小组关于阿片引起的痛觉过敏及其与损伤相互作用的工作 直到最近，潜在敏化作为慢性疼痛模型的重要性才变得清晰， 目前只有一项研究涉及其与神经性疼痛的相关性，该项目将研究其机制。 神经性疼痛中潜在致敏的具体目标是：1）研究阿片受体的作用和 神经病理性潜在敏化的应激；2)确定潜在敏化的缓解期是否为 由阿片类药物释放或 µ-阿片类药物受体组成活性介导；3) 研究 NMDAR 的作用和 我们将测试以下神经病理性潜伏敏化中的腺苷酸环化酶/蛋白激酶A途径。 假设：1）脊髓中的μ-阿片受体、κ-阿片受体和α2A肾上腺素受体介导 神经损伤引起的潜在敏化缓解期的抗痛觉过敏；2）μ-阿片受体； 3）位于初级传入末梢的应力有助于潜在敏化的缓解阶段； 在潜在致敏缓解阶段恢复疼痛痛觉过敏；4) µ-阿片受体组成型； 5) 潜在敏化中的疼痛敏感性为 通过正反馈环路维持，其中 NMDAR 和腺苷酸环化酶/蛋白激酶 A 通路 该项目将使用多学科方法来测试这些假设。 神经病理性疼痛的幸存神经损伤模型将用于大鼠和小鼠，以鉴定能够缓解神经性疼痛的受体 使用选择性删除μ-阿片类药物的转基因小鼠抑制缓解期的疼痛敏感性。 伤害性初级传入神经中的受体，我们将确定是否抑制疼痛的 µ-阿片受体 我们还将研究压力如何在缓解阶段恢复疼痛。 在目标 2 中，我们将确定 µ-阿片受体产生的抗痛觉过敏是否是由于其 通过使用膜片钳记录初级传入神经元来测量其对 另一种假设是，μ-阿片受体被持续激活。 阿片类药物的释放，将使用编码阿片类肽的三个基因被敲除的小鼠进行测试。 阿片类药物的释放将通过 µ-阿片类药物受体内化来测量。在目标 3 中，NMDA 之间的相互作用。 将在初级传入神经中研究潜在敏化过程中的受体、腺苷酸环化酶和蛋白激酶 A 使用钙成像和膜片钳对神经元进行蛋白质激活 NMDA 受体的磷酸化。 潜在致敏过程中的激酶 A 将通过蛋白质印迹进行测量。最后，NMDA 受体拮抗剂。 腺苷酸环化酶和蛋白激酶 A 的抑制剂和激活剂将用于描绘信号 这将确定开发药物逆转的目标。 神经性疼痛。