Brownlee D J, Walker R J
Divison of Cell Sciences, School of Biological Sciences, University of Southampton, England, UK.
Ann N Y Acad Sci. 1999;897:228-38. doi: 10.1111/j.1749-6632.1999.tb07894.x.
The endogenous nematode peptides known as FMRFamide-related peptides (FaRPs) and various "classical" transmitters have a range of effects on nematodes that result in changes in behavior, particularly locomotion, including paralysis and inhibition of feeding. This study describes the application of an in vitro pharmacological approach to further delineate the action of a number of FaRP neurotransmitters on feeding behavior. Contraction of Ascaris suum pharyngeal muscle was monitored using a modified pressure transducer system that detects changes in intrapharyngeal pressure and therefore contraction of the radial muscle of the pharynx. The pharynx did not contract spontaneously. However, serotonin (5-HT, 100 microM) stimulated rhythmic contractions and relaxations (pumping) at a frequency of 0.5 Hz. The native nematode peptide, KNEFIRFamide (AF1), inhibited the pumping elicited by 5-HT. The duration of inhibition was concentration-dependent (1-1000 nM) with a threshold of 1 nM (n = 7). KSAYMRFamide (AF8/PF3) also inhibited pharyngeal pumping. There was no observable effect of any of the following nematode peptides on pharyngeal pumping behavior (1-1000 nM; n = 8): AF2, AF3, AF4, AF6, AF16, PF1/CF1, PF2/CF2, or PF4. Thus, interruption of pharyngeal processes, such as feeding, regulation of hydrostatic pressure, and secretion, may provide a new site of anthelmintic action.
内源性线虫肽，即类FMRF酰胺相关肽（FaRPs）和各种“经典”递质，对线虫有一系列影响，会导致行为改变，尤其是运动行为，包括麻痹和摄食抑制。本研究描述了一种体外药理学方法的应用，以进一步阐明多种FaRP神经递质对摄食行为的作用。使用改良的压力传感器系统监测猪蛔虫咽肌的收缩，该系统可检测咽内压力变化，从而检测咽径向肌的收缩。咽不会自发收缩。然而，血清素（5-HT，100微摩尔）以0.5赫兹的频率刺激有节奏的收缩和舒张（抽吸）。天然线虫肽KNEFIRFamide（AF1）抑制了5-HT引起的抽吸。抑制持续时间呈浓度依赖性（1-1000纳摩尔），阈值为1纳摩尔（n = 7）。KSAYMRFamide（AF8/PF3）也抑制咽抽吸。以下任何一种线虫肽（1-1000纳摩尔；n = 8）对咽抽吸行为均无明显影响：AF2、AF3、AF4、AF6、AF16、PF1/CF1、PF2/CF2或PF4。因此，干扰咽的过程，如摄食、静水压力调节和分泌，可能提供一个新的驱虫作用位点。
