血水草生物碱对离体钉螺足跖平滑肌收缩的影响及与Ca^(2+)的关系

Role of calcium ion in effects of ECA on contractive activities of smooth muscles of Oncomelania foot

目的研究血水草生物碱(Eomecon chionantha Hance alkaloids,ECA)对钉螺足跖平滑肌收缩活动的影响及与Ca2+的关系,探讨其降低钉螺附壁上爬、增强灭螺效果的作用机制。方法采用离体平滑肌实验方法,观察ECA对钉螺足跖平滑肌收缩活动的影响。结果在有钙或无钙含乙二胺四乙酸二钠的Ringer’s液中,5．0、10．0、20．0 mg／L ECA均可使钉螺足跖平滑肌张力增加、收缩幅度减小、频率加快,且作用呈剂量依赖性。但在有钙情况下较在无钙液中强。结论 ECA可增加足跖平滑肌张力、减小收缩幅度、加快收缩频率,影响其收缩活动,此作用可能与ECA促外Ca2+内流及促内Ca2+释放的作用有关。这可能是投药后钉螺不能附壁上爬,增强灭螺效果的原因之一。

Objective To investigate the relationship between the calcium ion and the effects of ECA on the contraction of the smooth muscles of Oncomelania foot, and explore the mechanism of ECA in decreasing the snail climbing adhesion and increasing snail-killing. Method The in vitro experiment was used to observe the effects of ECA on contraction activities of foot smooth muscles of Oncomelania. Results ECA 5.0, 10.0, 20.0 mg/L. enhanced the resting tension, decreased the contraction range and increased the contraction frequency of the foot smooth muscles of Oncomelania in Ringer＇s solution with or without Ca^2＋ , with a characteristic of the dose-dependent, but stronger in solution with Ca^2＋ than that in solution without Ca^2＋. Conclusions ECA can enhance the resting tension, decrease the contraction range and increase the contraction frequency of the foot smooth muscles of Oncomelania. This suggested that ECA could be related to increasing the intracellular Ca^2＋ release and influx of the extracellular Ca^2＋. This could provide an explanation why ECA decreases the rate of Oncomelania climbing adhesion and enhances snail-killing.