Nociceptive Role of SST and NT receptor-expressing dorsal horn neurons

表达 SST 和 NT 受体的背角神经元的伤害感受作用

• 批准号: 8696769
• 负责人: RONALD Gordon WILEY
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8696769
• 关键词: Absence of pain sensation; Adenylate Cyclase; Adverse effects; Alcohol or Other Drugs use; Analgesics; Anatomy; Animal Model; Animals; Behavior; Behavioral; Biological Neural Networks; Brain; Brain Injuries; Caring; Cells; Cerebrum; Cholera Toxin A Subunit; Chronic; Chronic inflammatory pain; Clinical; Clinical Trials; Cordotomy; Cyclic AMP-Responsive DNA-Binding Protein; Cytotoxin; DNA; Data; Dose; Galanin; Gene Expression; Genes; Glutamates; Goals; Health; Hour; Human; Hyperalgesia; Interneurons; Intervention; Intractable Pain; Intrathecal Injections; Knockout Mice; Lesion; Long-Term Effects; Medicine; Mind; Modeling; Mus; Naloxone; Nerve; Neurologic; Neurons; Neuropathy; Neuropeptides; Neurotensin; Neurotensin Receptors; Neurotransmitter Receptor; Nociception; Nociceptive Reflex; Operative Surgical Procedures; Opiates; Opioid; Pain; Pathogenesis; Patients; Pharmaceutical Preparations; Phase; Plastics; Population; Post-Traumatic Stress Disorders; Posterior Horn Cells; Process; Protein Isoforms; Protein Kinase C; Proteins; Quality of life; Rattus; Reporting; Resistance; Role; Somatostatin; Somatostatin Receptor; Spinal Cord; Spinal Cord Part; Spinal cord posterior horn; Staining method; Stains; Substance P; Substantia Gelatinosa; Techniques; Testing; Therapeutic; Time; Veterans; Work; allodynia; arm; base; chronic neuropathic pain; chronic pain; clinically significant; dorsal horn; effective therapy; gene therapy; improved; inflammatory neuropathic pain; inflammatory pain; inhibitor/antagonist; neuromechanism; neuropathology; neuropeptide Y; novel; novel strategies; oncology; pain inhibition; painful neuropathy; preference; protein kinase C gamma; receptor; research study; response; substance P-saporin; success; targeted delivery; vector

DESCRIPTION (provided by applicant): Successful management of chronic pain is a major ongoing and unmet clinical challenge. The superficial dorsal horn (SDH) of the spinal cord has long been identified as the first key gateway for nociceptive information entering the CNS. Interventions applied at the level of the dorsal horn have the potential to selectively interdict the flow of specific types of nociceptive information to the brain with greater efficacy and fewer side effects than the currently available alternatives, medications or surgery. The focus of the present proposal are two types of inhibitory nocifensive neurons in the SDH and the therapeutic potential of two neuropeptides, which given intrathecally activate receptors on inhibitory SDH interneurons and produce analgesia in humans, somatostatin (SST), or anti-nociception in animals, neurotensin (NTS). Both of these neuropeptides are abundantly present in the SDH, and neurons with the cognate receptors are located in lamina II (substantia gelatinosa). SST receptors (sst2a) are expressed entirely on GABAergic inhibitory interneurons suggesting that SST produces naloxone-insensitive analgesia by exciting inhibitory interneurons that normally inhibit nociceptive projection neurons. Neurotensin is primarily excitatory, is produced/released by glutamatergic (excitatory) interneurons and also produces naloxone-insensitive anti-nociception by presumably exciting inhibitory interneurons which, in turn, inhibit nociceptive projection neurons. The aim of the present proposal is to evaluate SDH inhibitory interneurons as targets for achieving sustained, but ultimately reversible, non-opioid analgesia by enhancing the activity of these inhibitory nociceptive interneurons, i.e. reversing the inhibitory deficit thought important in the pathogenesis of chronic neuropathic pain. The specific study objectives for SST are: 1 - determine the precise anatomic effects (target cell loss, neuropathology) and nocifensive behavioral effects produced by lumbar intrathecal injection of the targeted cytotoxin, SST-saporin, in normal rats and rat models of chronic inflammatory and neuropathic pain; 2 - determine effects of tonically activating sst2a receptor-expressing SDH interneurons with lumbar intrathecal injection of SST-cholera toxin A subunit conjugate (SST-CTA) in normal rats and rat models of chronic inflammatory and neuropathic pain; and 3 - then determine the effects of lumbar intrathecal injection of SST conjugated to the gene for CTA (SST-polyplex-CTA DNA) in normal rats and rat models of inflammatory and neuropathic pain. The specific objectives for NTS are: 1 - determine the precise anatomic effects (target cell loss, neuropathology) and nocifensive behavioral effects produced by lumbar intrathecal the targeted cytotoxin, NTS-saporin, in normal rats and rat models of chronic inflammatory and neuropathic pain; 2 - determine effects of tonically activating NTS1 receptor-expressing SDH interneurons with lumbar intrathecal injection of NTS-cholera toxin A subunit conjugate (NTS-CTA) in normal rats and rat models of chronic inflammatory and neuropathic pain; and 3 - then determine the effects of lumbar intrathecal injection of NTS conjugated to the gene for CTA (NTS-polyplex-CTA DNA) in normal rats and rat models of inflammatory and neuropathic pain. Anatomic studies will determine efficacy and selectivity of the delivery of CTA or the CTA gene using immunohistochemical markers for excitatory and inhibitory neurotransmitters and receptors and for phosphoCREB (a marker for activation of adenylyl cyclase by CTA). Behavioral analyses will include a standard reflex nociceptive test (thermal plate lick/guard) and operant tests (thermal escape and thermal preference) that require cerebral participation in making choices based on the degree of discomfort. Preliminary results with NTS-saporin produces robust spontaneous behaviors (scratching) highly suggestive of ongoing discomfort and increased hotplate responses while lumbar intrathecal SST-saporin also showed spontaneous scratching. These novel strategies for tonically exciting inhibitory interneurons with CTA,may open a new chapter in the search for safer, more effective ways to manage chronic, intractable pain.

描述（由申请人提供）： 慢性疼痛的成功治疗是一个持续且尚未解决的重大临床挑战。脊髓的浅表背角（SDH）长期以来被认为是伤害性信息进入中枢神经系统的第一个关键门户。在背角水平应用的干预措施有可能选择性地阻止特定类型的伤害性信息流向大脑，与目前可用的替代方案、药物或手术相比，其疗效更高，副作用更少。本提案的重点是 SDH 中的两种类型的抑制性伤害性神经元以及两种神经肽的治疗潜力，这两种神经肽通过鞘内激活抑制性 SDH 中间神经元上的受体并在人类中产生镇痛作用、生长抑素 (SST) 或在动物中产生抗伤害作用，神经降压素（NTS）。这两种神经肽在 SDH 中大量存在，并且具有同源受体的神经元位于层 II（凝胶质）中。 SST 受体 (sst2a) 完全在 GABA 能抑制性中间神经元上表达，表明 SST 通过刺激通常抑制伤害性投射神经元的抑制性中间神经元来产生纳洛酮不敏感的镇痛。神经降压素主要是兴奋性的，由谷氨酸能（兴奋性）中间神经元产生/释放，并且还通过可能兴奋抑制性中间神经元产生纳洛酮不敏感的抗伤害性感受，而抑制性中间神经元反过来又抑制伤害性投射神经元。本提案的目的是评估 SDH 抑制性中间神经元作为通过增强这些抑制性伤害性中间神经元的活性来实现持续但最终可逆的非阿片类镇痛的目标，即逆转在慢性神经性疼痛发病机制中重要的抑制缺陷。 SST 的具体研究目标是： 1 - 确定腰椎鞘内注射靶向细胞毒素 SST-皂草素在正常大鼠和慢性炎症和慢性炎症大鼠模型中产生的精确解剖学效应（靶细胞丢失、神经病理学）和伤害行为效应。神经性疼痛；图2-确定通过腰椎鞘内注射SST-霍乱毒素A亚基结合物(SST-CTA)来强直性激活表达sst2a受体的SDH中间神经元对正常大鼠和慢性炎症和神经性疼痛的大鼠模型的影响； 3 - 然后确定腰椎鞘内注射与 CTA 基因 (SST-polyplex-CTA DNA) 缀合的 SST 对正常大鼠和炎症和神经性疼痛大鼠模型的影响。 NTS 的具体目标是： 1 - 确定腰椎鞘内注射靶向细胞毒素 NTS-皂草素在正常大鼠和慢性炎症和神经性疼痛大鼠模型中产生的精确解剖学效应（靶细胞损失、神经病理学）和伤害行为效应；图2-确定通过腰椎鞘内注射NTS-霍乱毒素A亚基缀合物(NTS-CTA)来强直性激活表达NTS1受体的SDH中间神经元对正常大鼠和慢性炎症和神经性疼痛的大鼠模型的影响； 3-然后确定腰椎鞘内注射与CTA基因缀合的NTS(NTS-polyplex-CTA DNA)对正常大鼠和炎症和神经性疼痛的大鼠模型的影响。解剖学研究将使用兴奋性和抑制性神经递质和受体以及磷酸CREB（CTA激活腺苷酸环化酶的标记物）的免疫组织化学标记物来确定CTA或CTA基因递送的功效和选择性。行为分析将包括标准的反射伤害性测试（热板舔/防护）和操作性测试（热逃逸和热偏好），需要大脑参与根据不适程度做出选择。 NTS-皂草素的初步结果产生强烈的自发行为（抓挠），高度暗示持续的不适和增加的热板反应，而腰椎鞘内 SST-皂草素也显示出自发的抓挠。这些通过 CTA 强直性兴奋抑制性中间神经元的新策略可能会为寻找更安全、更有效的方法来治疗慢性顽固性疼痛开启新的篇章。