Novel Analgesics from Australian Funnel-Web Spider Venom

痛觉感受器是人类痛苦和经济损失的主要来源，痛感外周神经元的激活引起的疼痛是人类痛苦的主要来源。伤害性感受器的激活和疼痛信号的传递到中枢神经系统，在那里它们引起对疼痛的有意识的感知，需要各种刺激和电压门控离子通道的协调参与。我们的长期目标是开发药物来干扰哺乳动物伤害性感受器中的离子通道功能，以缓解人类的疼痛。我们将使用一个新发现的自然产生的不同多肽离子通道毒素的组合库作为候选试剂的来源，这些毒素来自澳大利亚漏斗网蜘蛛的毒液。为了确定这个文库的成员具有理想的活性，我们将筛选他们针对已知对伤害性感受器功能重要的离子通道的活性。传递疼痛刺激的第一步是激活伤害性感受器质膜上的刺激门控离子通道，如极端高温或寒冷、有毒化学品、机械损伤或炎症介质。一旦疼痛刺激被刺激门控离子通道转换成电化学信号，它就必须作为沿着伤害性感受器轴突向下的电信号传递到中枢神经系统。痛觉信号传递到中枢神经系统需要激活伤害性感受器末端和轴突中的电压门控离子通道。我们将通过筛选非洲爪哇卵母细胞中克隆的伤害性感受器离子通道的抗毒素来识别伤害性感受器外周末端刺激和电压门控离子通道的阻断剂。一旦我们确定了对克隆的伤害性感受器离子通道具有活性的阿曲霉毒素的一个子集，我们将在急性培养的感觉神经节伤害性感受器中测试它们中的每一个与相应的天然通道。这一次级筛选对于排除那些对伤害性感受器质膜上天然状态的离子通道没有活性的阿曲霉毒素进行体内候选止痛药的研究是必不可少的。这些研究将确定作为治疗人类严重疼痛的新疗法的主要药物，与目前可用的药物相比具有显著的优势。特别是，通过靶向存在于伤害性感受器外周终端的离子通道，我们为外周疼痛部位的局部药物应用打开了可能性。一旦确定了这些先导药物，我们将与成熟的专家合作，在公认的临床前哺乳动物疼痛体内模型中测试这些药物。

Pain caused by activation of pain-sensing peripheral neurons ("nociceptors") is a major source of human suffering and economic loss. Activation of nociceptors and the transmission of pain signals to the central nervous system, where they give rise to the conscious perception of pain, requires the coordinated participation of a variety of stimulus- and voltage-gated ion channels. Our long-term goal is the development of pharmaceutical agents for interfering with the functions of ion channels in mammalian nociceptors to ameliorate human pain. We will employ as a source of candidate agents a newly-discovered naturally-occurring combinatorial library of diverse peptide ion channel toxins ("atracotoxins") derived from the venom of Australian funnel-web spiders. To identify members of this library with desirable activity, we will screen them for activity against ion channels known to be important for nociceptor function. The first step in the transduction of painful stimuli-such as extreme heat or cold, noxious chemicals, mechanical injury, or inflammatory mediators-is the activation of stimulus-gated ion channels in the plasma membrane of nociceptors. Once a painful stimulus is transduced by stimulus-gated ion channels into an electrochemical signal, it must be transmitted to the CNS as an electrical signal down the axon of the nociceptor. The transmission of pain signals to the CNS requires activation of voltage-gated ion channels in the endings and axons of nociceptors. We will identify blockers of stimulus- and voltage-gated ion channels in the peripheral terminals of nociceptors by screening atracotoxins against cloned nociceptor ion channels expressed in Xenopus laevis oocytes. Once we have identified a subset of atracotoxins that are active against cloned nociceptor ion channels, we will test each of them against the corresponding native channels in acutely cultured sensory ganglion nociceptors. This secondary screen is essential for excluding from future in vivo studies of candidate analgesics those atracotoxins that are inactive against ion channels in their native state in the nociceptor plasma membrane. These studies will identify lead pharmaceutical agents for use as novel treatments for severe human pain with significant advantages over those that are currently available. In particular, by targeting ion channels present in the peripheral terminals of nociceptors, we open up the possibility for local drug application to the site of peripheral pain. Once these lead agents are identified, we will collaborate with established experts to test these agents in accepted in vivo preclinical mammalian models of pain.