Integrative And Molecular Studies Of Pain And Pain Contr

我们的研究项目涉及中枢神经系统痛觉传递的基本分子和生理过程，以及治疗顽固性疼痛的新有效方法。分子研究是通过动物和体外细胞模型进行的。我们集中研究支配皮肤和深层组织的初级传入痛觉神经元及其在脊髓背侧的连接，脊髓背侧是突触信息处理痛觉的第一个部位。我们的研究已经确定它是神经元可塑性的一个位点，并改变了持续疼痛状态的基因表达。通过在异源细胞系统中异位表达和在背根神经节原代培养中自然表达的克隆热和化学反应离子通道，也在研究物理疼痛刺激的转导调节。我们的目标是(1)在神经系统的这两个基本水平上了解急性和慢性疼痛的分子和细胞生物学机制；(2)利用这些知识设计新的疼痛治疗方法。我们解决后一个目标的转化研究和人类临床试验计划，旨在评估新的镇痛治疗严重疼痛。我们正在开发的治疗方法是基于我们对通过香草样受体1 （TRPV1）进行疼痛转导的分子机制的研究。该分子是一种热感钙/钠离子通道，通过打开通道并使痛觉神经末梢去极化，将痛觉热量转化为神经动作电位。辣椒素是一种香草化学物质，也是辣椒中的活性成分，它也会刺激通道打开。我们使用一种非常有效的香草类似物来打开通道，导致一类特定的痛觉神经元死亡，但允许机械和高温热痛觉以及其他体感和本体感觉保持完整。我们已经与NIDA的药物治疗学和药物滥用的医学后果部门建立了一个研究所间工作组，将这种治疗方法带入人体临床试验。工作组由医学、神经生物学、毒理学、化学和制剂方面的专家以及我们小组的麻醉师、药理学家和病理学家组成。在这一年中，我们还建立了获取天然产物的机制，从天然产物中提取活性药物，以及药品的分离、纯化和配方程序，使其符合食品和药物管理局（FDA）的规定。我们目前正在完成毒理学研究，FDA的新药研究申请和NCI的IRB的人类临床协议。我们设计的治疗方法可能是一种非常有效的方法来控制许多类型的慢性疼痛，特别是那些与癌症、关节炎、颞下颌关节疾病、三叉神经痛和慢性神经性疼痛问题有关的疼痛。

Our research program addresses basic molecular and physiological processes of nociceptive transmission in the central nervous system and new, effective ways to treat intractable pain. The molecular research is performed using animal and in vitro cell-based models. We concentrate on primary afferent pain-sensing neurons that innervate the skin and deep tissues and their connections in the dorsal spinal cord, which is the first site of synaptic information processing for pain. Our research has identified it as a locus of neuronal plasticity and altered gene expression in persistent pain states. The regulation of transduction of physical pain stimuli is also under investigation using cloned thermal and chemo-responsive ion channels ectopically expressed in heterologous cell systems and naturally expressed in primary cultures of dorsal root ganglion. Our goals are (1) to understand the molecular and cell biological mechanisms of acute and chronic pain at these two basic levels of the nervous system and (2) to use this knowledge to devise new treatments for pain. We address the latter goal in a translational research and human clinical trials program designed to evaluate new analgesic treatment for severe pain. The treatment we are developing is based on our studies of the molecular mechanisms of pain transduction through the vanilloid receptor 1 (TRPV1). This molecule is a heat-sensing calcium/sodium ion channel that converts painful heat into nerve action potentials by opening the channel and depolarizing pain-sensing nerve terminals. Channel opening is also stimulated by capsaicin which is a vanilloid chemical and the active ingredient in hot pepper. We use a very potent vanilloid analog to prop open the channel causing death of a specific class of pain-sensing neurons, yet allowing mechanical and high temperature heat pain sensations and other somatosensory and proprioceptive sensations to remain intact. We have established an inter-institute working group with NIDA's Division of Pharmaco-Therapeutics and Medical Consequences of Drug Abuse to bring the treatment to human clinical trial. The working group consists of experts on medical, neurobiological, toxicological, chemical and formulation issues as well as anesthesiologists, pharmacologists and pathologists from our group. Over the course of this year, we also established mechanisms for obtaining the natural product from which the active drug is extracted and procedures for isolation, purification and formulation of the drug product such that it will be compliant with Food and Drug Administration (FDA) regulations. We are presently finalizing the toxicology study, the Investigational New Drug Application with the FDA and the Human Clinical Protocol with the NCI's IRB. The treatment we have devised may be a very effective approach to control many types of chronic pain especially those associated with cancer, arthritis, tempromandibular joint disorders, trigeminal neuralgia and chronic neuropathic pain problems. Underlying the translational studies are the questions of molecular regulation in chronic pain and mechanisms of pain transduction in peripheral nerve ending. These questions are addressed using subtraction cloning, differential hybridization and gene arrays, and neurophysiological measurements such as calcium imaging in live cells. The physiological stdies have focused on he multiple intracellular pools of calcium that can be activated by vanilloid agonists and the interaction of these pools with the plasma membrane localized TRPV1 and TRPV1 located on the endoplasmic reticulum. Activation of TRPV1 in both locations is a factor that underlies the efficacy of TRPV1 agonists at inducing calcium cytotoxicity in the above translational studies. The molecular studies reveal a more dynamic modulation of gene expression in dorsal root ganglion than previously hypothesized, for example, in a matter of hoours we observe up-regulation of the receptor for Neuropeptide FF, which is known to be involved in opioid modulation of pain. In addition to pain, these studies fundamentally explore the molecular basis of synaptic plasticity. New roles for the calcium and arachidonic acid binding proteins S100A8 and S100A9 in spinal cord and dorsal root ganglion have also been discovered. We hypothesize modularity in the neuronal response new levels of synaptic or pharmacological input (e.g. learning, neurological disorders, drug abuse). The "generic" alterations are combined with modulation of tissue-specific genes to meet the demands generated by the new level of stimulation. This will lead to a deeper understanding of molecular mechanisms that trigger and sustain chronic pain.