Glutamate-evoked calcium signaling in spinal cord after nerve injury

神经损伤后脊髓中谷氨酸诱发的钙信号传导

• 批准号: 8536968
• 负责人: Suzanne Doolen
• 金额: $ 7.17万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8536968
• 关键词: 6-Cyano-7-nitroquinoxaline-2,3-dione; AMPA Receptors; Action Potentials; Adult; Adverse effects; Analgesics; Animals; Astrocytes; Attenuated; Behavior; Behavioral; Calcium; Calcium Signaling; Cells; Chemosensitization; Chronic; Data; Development; Dose; Frequencies; Fura-2; Glutamate Receptor; Glutamates; Goals; Healthcare; Hyperalgesia; Hypersensitivity; Image; Injury; Knowledge; Label; Lead; Ligation; Measures; Mediating; Mission; Modeling; Mus; Nerve; Neurons; Operative Surgical Procedures; Pain; Pain Measurement; Pain management; Peripheral Nerves; Peripheral nerve injury; Physiological; Population; Posterior Horn Cells; Receptor Signaling; Relative (related person); Research; Signal Transduction; Skin; Slice; Specificity; Spinal Cord; Stimulus; Substantia Gelatinosa; Tactile; Techniques; Testing; Time; Variant; allodynia; base; cell type; central pain; central sensitization; chronic pain; clinically relevant; dorsal horn; inhibitor/antagonist; injured; innovation; kainate; nerve injury; neurotransmission; painful neuropathy; response; sciatic nerve; spinal nerve posterior root; therapeutic target

DESCRIPTION (provided by applicant): A fundamental gap exists in understanding the cellular mechanisms that initiate and maintain neuropathic pain. This gap represents an important problem because current analgesic drugs rarely provide sufficient efficacy without serious side effects. The long-term goal is to understand the mechanisms that lead to injury-induced central sensitization and establish clinically relevant therapeutic targets for chronic pai. The objective in this application is to evaluate the contribution glutamate receptor subtypes to dorsal root stimulation (DRS)-evoked Ca2+ transients in the dorsal horn, and correlate enhanced Ca2+ responses with the magnitude of pain-like behavior. Based on preliminary data suggesting that glutamate-evoked Ca2+ responses in mouse spinal cord slices are potentiated after nerve injury, the central hypothesis is that nerve injury increases AMPA receptor signaling in the dorsal horn, leading to increases in [Ca2+]i that results in central sensitization and neuropathic pain. The rationale for the proposed project is that [Ca2+]i in dorsal horn neurons is essential for central sensitization and pain hypersensitivity. The central hypothesis will be teste by pursuing three specific aims: AIM 1 tests the hypothesis that glutamate-mediated activation of neuronal ionotropic AMPA receptors drives Ca2+ signaling. Electrophysiological recordings and real-time fluorescent labeling of astrocytes will be used to evaluate the cell types that respond to dorsal root stimulation (DRS) with a rise in [Ca2+]i. Next, the relative contribution of glutamate receptor subtypes will be determined by quantifying DRS-evoked [Ca2+]i transients in the presence of selective antagonists. AIM 2 tests the hypothesis that peripheral nerve injury potentiates DRS-evoked Ca2+ responses, and this will correlate with the magnitude of hyperalgesia. To allow for a correlation analysis between behavior and [Ca2+]i, a variant model of nerve injury has been developed that gradually elicits robust allodynia in 1 week and then resolves in 4 weeks. Behavioral hyperalgesia will be evaluated and compared to DRS-evoked [Ca2+]i in spinal cord slices from sham, traditional and variant nerve injured animals sacrificed at 7, 14 and 21 d after injury. AIM 3 tests the hypothesis that PKM¿ mediates SNI-induced increases in hyperalgesia, Ca2+ signaling and AP frequency in dorsal horn. We will administer multiple PKM¿ inhibitors to sham and SNI mice and measure pain- like behavior, Ca2+ transients and/or AP frequency. Based on our preliminary results, we predict that PKM¿ blockade will reverse injury-induced hyperalgesia, increases in [Ca2+]i and AP frequency. This project employs innovative wide-field calcium imaging simultaneously from numerous cells in spinal cord slices from adult mice. The proposed research is significant because it reveals the Ca2+ channels that regulate DRS-evoked Ca2+ transients, and is a critical first step in understanding nerve injury-induced potentiation of neuronal Ca2+ signaling. Ultimately, this knowledge will establish clinically relevant therapeutic targets for alleviating chronic pain.

描述（由申请人证明）：理解引发和维持神经性疼痛的细胞机制，因为当前的药物重新提供了副作用。在此应用中，安属 - 建立the脚的豆胶PAI。表明在小鼠脊髓切片中诱发的谷氨酸诱发的Ca2+ respon+ respon+ respon+ respon+ respon+ ses被增强，中心假设是在背角中的神经增加的受体信号。疼痛。在背角神经元中尤其是中心。刺激（drs），下一个i。 谷氨酸受体亚型将通过在存在选择性拮抗剂的情况下量化DRS诱发的[Ca2+] i的转移。相关性分析行为和[Ca2+] I，已经开发了一种神经的变异模型，可在1周内引起健壮的ODYNIA，然后在4周内消退。 tpkm¿介导SNI诱导率增加了Hypergeria，Ca2+信号传导和AP频率。对假ANI小鼠的抑制剂测量疼痛样行为，Ca2+瞬态和/或AP在PKM缺封锁会造成损伤引起的高温，[CA2+] I和AP频率同时从成年小鼠的脊髓中同时衰老。将建立与临床相关的治疗靶标，以减轻疼痛。