REGULATION OF PHARYNGEAL PUMPING IN PARASITIC NEMATODES

描述(申请人提供)：生物胺，如5-羟色胺、酪胺、章鱼胺和多巴胺，调节寄生线虫的一些关键过程，包括取食、咽泵、运动、产卵和许多更复杂的行为。在之前的资助期间，我们已经开始研究自由生活线虫和寄生线虫中一些生物胺受体的药理、偶联和定位，目的是识别调控这些关键过程的特定受体。在这些研究过程中，我们还发现了一个新的酪矿信号通路和突触前5-羟色胺受体连接的信号复合体，它们由一个含有支架蛋白的多PDZ结构域定位，似乎是有效的信号转导所必需的。本研究致力于确定猪蛔虫体内调节咽泵的生物胺受体，假设干扰这些受体，特别是通过刺激抑制输入，如伊维菌素和谷氨酸门控氯离子通道，将对蠕虫产生有害影响。此外，我们假设受体定位对于有效的信号转导可能与受体功能一样重要，并计划在这些多蛋白信号复合体的其他成分通过直接蛋白质相互作用和体内共定位得到确认后，使用突变体和“显性否定”方法来检验这一假设。

DESCRIPTION (provided by the applicant): Biogenic amines, such as serotonin, tyramine, octopamine and dopamine regulate a number of key processes in parasitic nematodes, including, feeding, pharyngeal pumping, locomotion, egg-laying and many more complex behaviors. During the previous grant period, we have begun to characterize the pharmacology, coupling and localization of a number of biogenic amine receptors in both free-living and parasitic nematodes with the goal of identifying the specific receptors regulating these key processes. During the course of these studies, we have also identified a novel tyraminergeric signaling pathway and presynaptic 5-HT receptor-linked signaling complexes that are localized by a multi-PDZ domain containing scaffolding protein that appear to be essential for efficient signal transduction. The present study is focused on the definitive identification of the biogenic amine receptors regulating pharyngeal pumping in the parasitic nematode, Ascaris suum, on the assumption that interference with these receptors, especially by stimulating inhibitory inputs, as has been described for ivermectin and glutamate-gated chloride channels, will have a deleterious effect of the worms. In addition, we hypothesize that receptor localization can be as important as receptor function for effective signal transduction and plan to test this hypothesis using mutants and a "dominant negative" approach, once the other components of these multi-protein signaling complexes have been confirmed by direct protein interaction and in vivo co-localization.