Integrative And Molecular Studies Of Pain And Pain Contr

我们的研究项目涉及中枢神经系统伤害性传递的基本分子和生理过程。该研究计划是垂直整合的，并使用分子生物学，体外细胞模型，动物模型和人类受试者。我们集中研究脊髓背侧的初级传入痛觉神经元及其联系。背侧脊髓是伤害性感觉突触加工的第一个部位，也是持续性疼痛中神经元可塑性和基因表达改变的场所。使用疼痛患者和正常志愿者的体内功能性脑成像，对人类进行与更高CNS疼痛处理相关的问题。该单位还研究了严重顽固性疼痛的新疗法，其中一种使用香草素受体1的基本分子机制。这种分子是一种热敏钙/钠离子载体，通过使皮肤中的痛觉神经末梢去极化，将疼痛的热量转化为神经动作电位。离子载体活性也被辣椒素（一种典型的香草素化学物质）和辣椒中的活性成分的结合所刺激。超强效香草素对这种受体的激活是如此强烈，以至于钙离子的增加会杀死细胞。这种体外观察直接导致了一个从实验室到床边的计划，其中香草素激动剂被用来杀死疼痛感应神经元，从而提供长期的疼痛控制。我们还表明，香草素受体在酸性条件下（如在炎症和组织损伤中发现的）对损伤期间细胞释放的分子敏感。这一观察结果的重要性在于，疼痛感知能力在损伤后得到维持和增强。我们发现，VR 1是磷酸化的PKC-α亚型表明，VR 1是一个点的多模态收敛的疼痛刺激。这促使我们寻找VR 1离子通道的阻断剂，这种阻断剂对所有形式的疼痛刺激都有效。该计划产生了镇痛化合物的新线索，并对VR 1的离子载体结构域的分子性质有了新的认识。第二个项目是集中在基因发现脊髓使用减法克隆和差异杂交，以确定新的基因引起的疼痛刺激。我们已经完成了第一次减法克隆疼痛状态基线，并打印了这些基因的微阵列。对阵列进行探测并重新网格化以将高表达的转录物与低丰度转录物分离，并且新阵列差异杂交。我们目前正在研究被激活的基因家族。除了疼痛，这些研究从根本上探索一般突触可塑性的分子基础，因为我们假设神经元对新水平的突触或药理学输入（例如学习，神经系统疾病，药物滥用）的反应具有模块性。在转化研究方面，我们的主要活动集中在使用超强效香草素树脂毒素（RTX）删除初级传入疼痛感受神经元。结果表明，RTX提供了一种基于机制的，解剖学导向的方法来控制慢性疼痛。目前，我们正在收集IND申请和临床方案，用于在患有晚期转移性疾病相关疼痛的人类受试者中使用RTX。

Our research program addresses basic molecular and physiological processes of nociceptive transmission in the central nervous system. The research program is vertically integrated and uses molecular biology, in vitro cell-based models, animal models and human subjects. We concentrate on the primary afferent pain sensing neurons and their connections in the dorsal spinal cord. The dorsal spinal cord is the first site of synaptic processing for nociceptive sensations and a locus of altered neuronal plasticity and gene expression in persistent pain. Questions related to higher CNS pain processing are performed with humans using in vivo functional brain imaging of pain patients and normal volunteers. The Unit also investigates novel treatments for severe intractable pain, one of which uses the basic molecular mechanisms of the vanilloid receptor 1. This molecule is a heat-sensitive calcium/sodium ionophore and converts painful heat into nerve action potentials by depolarizing the pain-sensing nerve terminals in the skin. Ionophore activity also is stimulated by binding of capsaicin, a prototypical vanilloid chemical, and the active ingredient in hot pepper. Activation of this receptor with ultra-potent vanilloids can be so strong that the increase in calcium kills the cell. This in vitro observation has directly led to a bench-to-bedside program in which vanilloid agonists are used to kill pain-sensing neurons and thereby provide long-term pain control. We have also shown that the vanilloid receptor is sensitized in acidic conditions (as are found in inflammation and tissue damage) to molecules released by cells during injury. The importance of this observation is that the pain sensing capacity is maintained and enhanced following injury. We showed that VR1 is phosphorylated by the PKC-alpha isoform suggesting that VR1 is a point of multimodal convergence of pain stimuli. This stimulated us to find blockers of the VR1 ion channel that would be effective across all forms of pain stimuli. The program has yielded new leads for analgesic compounds and new insights into the molecular nature of the ionophore domain of VR1. A second program is centered on gene discovery in spinal cord using subtraction cloning and differential hybridization to identify new genes induced by pain stimuli. We have completed the first subtraction cloning of pain state-baseline and have printed a microarray of these genes. The arrays were probed and re-gridded to segregate highly expressed from low abundance transcripts and the new array differentially hybridized. We are currently examining the families of genes that are activated. In addition to pain these studies fundamentally explore the molecular basis of synaptic plasticity in general, as we hypothesize a modularity in the neuronal response to a new level of synaptic or pharmacological input (e.g. learning, neurological disorders, drug abuse,). In terms of translational research our main activity has centered on deletion of primary afferent pain sensing neurons using the ultra-potent vanilloid resiniferatoxin (RTX). The results indicate that RTX provides a mechanism-based, anatomically directed approach to control of chronic pain. Presently, we are assembling the IND application and the clinical protocol for use of RTX in human subjects suffering from pain associated with advanced metastatic disease.