REGULATION OF PHARYNGEAL PUMPING IN PARASITIC NEMATODES

丝虫、钩虫和各种肠道线虫感染了全世界数十亿人，而家畜和栽培植物的线虫寄生虫对目前使用的抗线虫药物产生了数十亿美元的影响，线虫化疗的未来方向尚不确定。显然，新的收缩是所有线虫的基本过程，5-羟色胺（5-HT）受体在这两者的调节中起关键作用，本研究旨在鉴定和表征5-HT受体在寄生线虫中。具体来说，我们将使用RT-PCR技术对来自其他生物的5-HT受体保守区域设计退化寡核苷酸，以及从A. suum咽和体壁肌肉中分离的聚A+RNA制备cDNA库来鉴定来自咽和体壁肌肉的推定5-HT受体。然后，假定的5-HT受体，特别是最近发现的5- ht2样受体异构体，将在哺乳动物细胞系中功能性表达，以及壁肌的药理学和偶联以及5-HT依赖的腺苷环化酶活性、磷酸肌肽转换和咽部泵送的变化在猪咽或体壁肌的生理制剂中。这些研究应该清楚地描述5-羟色胺受体在线虫咽泵和肌肉收缩/代谢的调节中的作用，并为开发这些基本过程的特异性抑制剂提供一个很好的框架。

Filarids, hookworms and a variety of intestinal nematodes infect billions of individuals worldwide, while nematode parasites of domesticated animals and cultivated plants have a multibillion dollar impact on the anti-nematodal drug in use today the future direction of nematode chemotherapy is uncertain. Clearly, new contraction are essential processes in all nematodes and serotonin (5-HT) receptors play a key role in the regulation of both, the present study was designed to identify and characterize 5-HT receptors in the parasitic nematode Ascaris suum. Specifically, putative 5-HT receptors from pharynx and body wall muscle will be identified using RT-PCR with degenerate oligonucleotides designed against conserved regions of 5-HT receptors from other organisms and cDNA pools prepared from poly A+RNA isolated from A. suum pharynx and body wall muscle. Then, the putative 5-HT receptors, especially the recently identified 5-HT2-like receptor isoforms, will be functionally expressed in mammalian cell lines and the pharmacology and coupling of the wall muscle and 5-HT dependent changes in adenyl cyclase activity, phosphoinositide turnover and pharyngeal pumping in physiological preparations of A. suum pharynx or body wall muscle. These studies should generate a clear description of the role of 5-HT receptors in the regulation of pharyngeal pumping and muscle contraction/metabolism in nematodes and should provide an excellent framework for the development of specific inhibitors of these essential processes.