Spinal Cord-Mediated Acute Neurogenic Inflammation

描述（由申请人提供）：神经源性炎症有助于许多临床相关状态，包括关节炎，炎症性肠病，慢性支气管炎，偏头痛和间质性膀胱炎。已知这种类型的炎症是由感觉神经末梢释放炎性物质引起的，由此可引起甚至加重疼痛感觉。为了研究其机制，我们通过皮内注射辣椒素（CAP）实验建立了急性神经源性炎症模型。这些研究的长期目标是阐明神经源性炎症是如何通过瞬时受体电位香草素-1 （TRPVO）受体的激活而启动的，然后通过触发中枢介导的反胺活性、背根反射（DRRs）来加剧炎症性疼痛来维持的，以及交感-感觉相互作用如何调节神经源性炎症。揭示这些机制将导致抗炎疗法的改进。本提案的总体假设是，通过皮内注射CAP或组织损伤激活TRPV-i受体，引发神经源性炎症，然后通过触发DRRs维持和发展。交感-感觉相互作用通过激活信号转导级联，如蛋白激酶C (PKC)，调节TRPVi受体的功能活性，从而调节神经源性炎症。具体目的1是确定CAP注射后的神经源性炎症是否涉及触发DRRs，导致降钙素基因相关肽和/或P物质从初级传入伤害感受器释放，以及这一过程是否会反过来增强CAP诱导的初级传入伤害感受器的致敏，并分析这一过程是否由TRPN/激活启动！受体。具体目标2是检查是否激活PX/！初级传入伤害感受器中的受体通过激活背角回路中的gaba能中间神经元，在增强DRRs中起重要作用。特异性目的3是确定当神经源性炎症启动和发展时，PKC的磷酸化是否发生在初级传入神经元中，以及PKC的磷酸化是否上调TRPN/T受体。特异性目的4是研究通过PKC级联调节TRPNA受体的功能，是否通过释放去甲肾上腺素和腺苷5'-三磷酸对神经源性炎症的交感作用。实验方法包括电生理记录和参与伤害性信号转导的蛋白质的药理学调节，血流和爪厚测量以反映CAP注射诱导的神经源性炎症，以及免疫组织化学和Western blotting研究以分析CAP注射前后磷酸化受体和PKC表达的变化。

DESCRIPTION (provided by applicant): Neurogenic inflammation contributes to many clinically relevant states, including arthritis, inflammatory bowel disease, chronic bronchitis, migraine and interstitial cystitis. Such a type of inflammation has been known to be initiated by release of inflammatory substances from sensory nerve terminals by which painful sensation may be caused and even exacerbated. In order to investigate its mechanisms, we have experimentally established an acute model of neurogenic inflammation by using an intradermal capsaicin (CAP) injection. The long-term goal of the proposed studies is to elucidate how neurogenic inflammation is initiated by activation of transient receptor potential vanilloid-1 (TRPVO receptors, then maintained by triggering the centrally mediated antidromic activity, dorsal root reflexes (DRRs) to exacerbate inflammatory pain, and how sympathetic-sensory interactions modulate the neurogenic inflammation. Uncovering these mechanisms will lead to improvements in anti-inflammatory therapies. The overall hypothesis of the present proposal is that activation of TRPV-i receptors either by intradermal injection of CAP or tissue injury initiates neurogenic inflammation that will then be maintained and develops by triggering DRRs. Sympathetic-sensory interactions modulate the neurogenic inflammation by regulating the functional activity of TRPVi receptors via activating signal transduction cascades, such as protein kinase C (PKC). Specific Aim 1 is to determine if neurogenic inflammation following CAP injection involves triggering DRRs that cause the release of calcitonin gene-related peptide and/or substance P from primary afferent nociceptors and if this process would in turn enhance the CAP-induced sensitization of primary afferent nociceptors, as well as analyze if this process is initiated by activation of TRPN/! receptors. Specific Aim 2 is to examine if activation of the PX/! receptors in primary afferent nociceptors plays an important role in enhancing DRRs by activating GABAergic interneurons in dorsal horn circuits. Specific Aim 3 is to determine if phosphorylation of PKC takes place in the primary afferent neurons when neurogenic inflammation is initiated and develops, and if TRPN/T receptors are up-regulated by the phosphorylation of PKC. Specific Aim 4 is to examine if sympathetic effects on neurogenic inflammation by release of norepinephrine and adenosine 5'-triphosphate are done by modulating the function of TRPNA, receptors via the PKC cascade. The experimental approaches that will be used include electrophysiological recordings and pharmacological modulation of proteins involved in nociceptive signal transduction, blood flow and paw-thickness measurements to reflect neurogenic inflammation induced by CAP injection, and immunohistochemical and Western blotting studies to analyze changes in the expression of phosphorylated receptors and PKC before and after CAP injection.