Analgesic Signaling in Drosophila

止痛是一种抑制对可能损害组织的伤害性刺激的伤害性反应，是一种 生物体的适应性行为反应--允许他们在生理上适当的情况下感觉到较少的疼痛 身体创伤或战斗/逃跑反应等情况。传统上对止痛的研究是在 脊椎动物模型，内源性阿片肽与其同源受体结合以抑制行为 对痛苦刺激的反应。遗传上易驯化的模式生物，如果蝇，最近已经被使用 探讨组织损伤后伤害性感受和伤害性敏感化的分子/遗传学基础 尚未被用于剖析保守的镇痛信号。果蝇提供了遗传分析的两种速度 以及用于分析基因表达和功能的各种复杂的遗传工具，这些工具应该证明 对现有的研究止痛的实验范例有价值的补充。我们在这方面的长期目标 基础研究项目是鉴定和表征果蝇幼虫的止痛信号通路。那 这种途径很可能存在，我们的初步发现证明，阿片类化合物吗啡是 果蝇幼虫的止痛药以及保守的G蛋白偶联受体(GPCR)在这方面的作用 用于热镇痛的生物体。给苍蝇幼虫喂食吗啡引起跨越多个部位的一过性镇痛 感觉方式(热、冷、触摸、化学)，可被其他阿片类药物(芬太尼)模仿，部分是纳洛酮 可逆的。我们在最初项目期间的短期目标将是确定以下项目所需的GPC的特征 热止痛。利用我们对哪些组织表达gpr的知识，我们将确定哪些组织 在功能上要求它用于止痛，并评估假定受体的止痛作用是否延伸到其他 热以外的感官方式。在生化水平上，我们将测试GPCR(它是最清楚的人类 直链同源异构体)直接与吗啡结合以激活信号。在基因水平上，我们将识别内源性多肽 配体(S)和探针与已知的伤害性基因的遗传相互作用和伤害性敏化 信号通路。在我们的最终目标中，我们将探索吗啡给药对细胞的影响(钙变化)。 以及是否已知吗啡的有害生物副作用、耐受性和便秘的发展 在我们的新模型中也观察到了。成功完成这些目标将提供全面的蜂窝 在这一新模型中对止痛信号的遗传分析--可能产生可测试的基本信息 脊椎动物模型中正在进行的工作的假设。展望未来，这一新的止痛信号模型将 提供了无偏见的基因发现方法的可能性，这种方法应该允许识别新的 止痛所需的保守基因-在某些情况下可能与人类和 健康，值得在脊椎动物模型和临床环境中进一步探索。

Analgesia, the dampening of nociceptive responses to noxious stimuli capable of damaging tissues, is an adaptive behavioral response for organisms- allowing them to feel less pain in physiologically appropriate situations such as physical trauma or the fight/flight response. Analgesia has traditionally been studied in vertebrate models, where endogenous opioid peptides bind to their cognate receptors to dampen behavioral responses to painful stimuli. Genetically tractable model organisms such as Drosophila have recently been used to explore the molecular/genetic bases of nociception and nociceptive sensitization following tissue injury but have not yet been used to dissect conserved analgesia signaling. Drosophila offer both speed of genetic analysis and a variety of sophisticated genetic tools for analyzing gene expression and function that should prove a valuable complement to existing experimental paradigms for the study of analgesia. Our long-term goal in this basic research project is to identify and characterize analgesic signaling pathways in Drosophila larvae. That such pathways are likely to exist is evidenced by our preliminary findings that the opiate compound morphine is analgesic for Drosophila larvae and that a conserved G-protein coupled receptor (GPCR) is required in this organism for thermal analgesia. Morphine feeding to fly larvae causes transient analgesia that spans multiple sensory modalities (heat, cold, touch, chemical), is mimicked by other opiates (fentanyl) and is partially naloxone reversible. Our short-term goals over the initial project period will be to characterize the GPCR required for thermal analgesia. Using our knowledge of which tissues express the GPCR we will determine which tissues functionally require it for analgesia, and assess whether the putative receptor’s analgesic effects extend to other sensory modalities beyond heat. At the biochemical level we will test whether the GPCR (and it’s clearest human ortholog) directly binds morphine to activate signaling. At the genetic level we will identify endogenous peptide ligand(s) and probe genetic interactions with previously identified nociceptive genes and nociceptive sensitization signaling pathways. In our final aim we will probe cellular effects of morphine administration (calcium changes) and whether known deleterious biological side effects of morphine, development of tolerance and constipation are also observed in our new model. Successful completion of these aims will provide a comprehensive cellular and genetic analysis of analgesic signaling in this new model- basic information that is likely to generate testable hypotheses for ongoing work in vertebrate models. Moving forward, this new model of analgesic signaling will provide the possibility of unbiased gene discovery approaches that should allow for identification of novel conserved genes required for analgesia- targets that may in some cases be potentially relevant to human and health and worthy of further exploration in vertebrate models and clinical settings.