Novel Analgesics from Australian Funnel-Web Spider Venom

由痛觉外周神经元（“痛觉感受器”）激活引起的疼痛是人类痛苦和经济损失的主要来源。痛觉感受器的激活和疼痛信号向中枢神经系统的传递，在中枢神经系统中引起对疼痛的有意识感知，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干扰哺乳动物伤害感受器离子通道功能的药物，以改善人类的疼痛。我们将采用从澳大利亚漏斗网蜘蛛的毒液中提取的多种肽离子通道毒素（“atracotoxins”）的新发现的天然组合文库作为候选药物的来源。为了确定该文库中具有理想活性的成员，我们将筛选它们对已知对伤害感受器功能重要的离子通道的活性。痛觉刺激（如极热或极冷、有毒化学物质、机械损伤或炎症介质）转导的第一步是痛觉感受器质膜中刺激控制离子通道的激活。一旦疼痛刺激被刺激门控离子通道转导成电化学信号，它必须作为电信号沿着伤害感受器的轴突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痛觉感受器末端和轴突的电压门控离子通道。我们将通过筛选针对非洲爪蟾卵母细胞中表达的克隆伤害感受器离子通道的atracotoxins，来鉴定伤害感受器外周末端刺激和电压门控离子通道的阻滞剂。一旦我们确定了对克隆的伤害感受器离子通道有活性的阿特拉毒素子集，我们将测试它们对急性培养的感觉神经节伤害感受器中相应的天然通道的作用。这种二次筛选对于排除未来候选镇痛药的体内研究至关重要，这些候选镇痛药是在伤害感受器质膜的天然状态下对离子通道无活性的白术毒素。这些研究将确定领先的药物制剂，用于治疗严重人类疼痛的新方法，比目前可用的药物有显着优势。特别是，通过靶向存在于伤害感受器外周末端的离子通道，我们开辟了局部药物应用于外周疼痛部位的可能性。一旦确定了这些主要药物，我们将与知名专家合作，在公认的体内临床前哺乳动物疼痛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.