Abstract: bjective To investigate the molluscicidal mechanism of combining use of the extract of Glycyrrhiza uralensis （GE） and niclosamide （Nic）. Methods The Oncomelania hupensis snails were immersed in Nic， GE and GE+Nic solutions for 24 h and 48 h respectively， and then were put into fresh water to confirm their survival condition. The alive ones were dissected to obtain their livers. The effects of the drugs on the protein and glycogen of the liver of O. hupensis were observed， and the effects on contractile activity of vola pedis of the snails were studied by the experimental method of isolated smooth muscles of O. hupensis. Results GE had no obvious effects on the protein and glycogen in the liver of O. hupensis （all P > 0.05）， but it could inhibit the contractions and decrease the contractile frequency of smooth muscles of vola pedis of O. hupensis （all P < 0.05）. Nic could significantly decrease the levels of protein and glycogen in the liver of O. hupensis （all P < 0.05）， as well as enhance the contractions and contractile frequencies of smooth muscles of vola pedis of O. hupensis （P < 0.05）. GE combined with Nic could further decrease the levels of protein and glycogen in the liver of O. hupensis （all P < 0.05）， meanwhile， it could inhibit the contractions and decrease the contractile frequency of smooth muscles of vola pedis of O. hupensis （all P < 0.05）. Conclusions The combining use of GE and Nic can accelerate the liver damage of O. hupensis， and also can inhibit the contractions of smooth muscles of vola pedis of O. hupensis which increases the contacting time of the drug， thus leads to the synergism of molluscicidal effect.

Key words: Oncomelania hupensis； Molluscicidal effect； Glycyrrhiza uralensis； Niclosamide； Liver； Glycogen； Protein； Smooth muscle； Vola pedis

摘要： 目的 探索甘草提取物与氯硝柳胺联合用药的灭螺机制。方法 采用室内浸杀法，以氯硝柳胺（Nic）、甘草提取物（GE）、GE+Nic浸泡钉螺24、48 h后，以水养法检测存活情况后，选活螺解剖，分离肝脏后观察不同药物对钉螺肝脏蛋白质、糖原水平的影响。利用离体钉螺平滑肌实验方法观察上述不同药物对钉螺足跖平滑肌收缩活动的影响。结果 甘草提取物对钉螺肝脏的蛋白质及糖原水平并无显著影响（P均 > 0.05），但能显著抑制钉螺足跖平滑肌的收缩，降低收缩频率（P均 < 0.05）；氯硝柳胺能显著降低钉螺肝脏的蛋白质及糖原水平（P均 < 0.05），且可增强钉螺足跖平滑肌的收缩强度和收缩频率（P均 < 0.05）；甘草提取物与氯硝柳胺联用后能进一步降低钉螺肝脏的蛋白质及糖原水平，且能够抑制钉螺足跖平滑肌的收缩，降低收缩频率（P均 < 0.05）。结论 甘草提取物与氯硝柳胺联用能加速对钉螺肝脏的损伤，同时可抑制其足跖平滑肌的活动，增加药物接触时间，达到灭螺增效作用。

关键词: 钉螺；灭螺效果；甘草；氯硝柳胺；肝脏；糖原；蛋白质；平滑肌；足跖