皂苷提取物宫血宁缩宫作用与细胞外钙内流关系的研究

Gongxuening′s uterotonic activity and relationship with extracellular calcium ion′s inward flow

目的探讨皂苷类提取物宫血宁引起的大鼠离体子宫收缩作用与细胞外钙内流的关系。方法应用离体子宫张力测定法,观察不同Ca2+浓度及Ca2+通道阻滞剂对宫血宁引起的大鼠离体子宫收缩作用的影响。结果无钙的台氏平衡液中,宫血宁的浓度从25μg/ml增至200μg/ml都不能引起大鼠离体子宫节律性收缩;在半钙和全钙的台氏平衡液中宫血宁能引起大鼠离体子宫节律性收缩,并与宫血宁的剂量呈显著正相关;Ca2+通道阻滞剂能明显抑制宫血宁和缩宫素引起的子宫收缩,但同缩宫素相比,宫血宁引起的子宫收缩对Ca2+通道阻滞剂更敏感。结论皂苷类提取物宫血宁的缩宫作用依赖于细胞外钙的存在,其作用机制可能是通过促进平滑肌细胞外钙内流来实现的。

Objective To study the relation of calcium entry into myometrium and uterus phasic contraction in vitro induced by a saponin extract:gongxuening. Methods Tension measurement of rat myometrium strips was used to observe the effect of nitrendipine and verapamil (calcium channel blockers) on the tensility change of rat myometrium strips which was induced by gongxuening. Results Gongxuening 50 μg/ml could induce phasic uterus contractions in Machfield Krebs′solution and in calcium-free solution. The phasic uterus contractions were not observed with the concentration of gongxuening from 25 μg/ml to 200 μg/ml.In the solution with a half concentration of calcium,the amplitude and frequence of uterus contraction induced by different concentrations of gongxuening were significantly lower than those in common solution of calcium channel blockers,such as nitrendipine and verapamil;the inhibition of uterus contraction induced by gongxuening and oxytocin was in dose-dependent manner,but the uterus contraction induced by gongxuening was more sensitive to calcium channel blockers than that induced by oxytocin. Conclusion Gongxuening is a saponin extract,its uterotonic effect depends on the occurrence of extracellalar calcium;the action mechanism may ascribe to promoting the smooth muscle′s extracellular calcium ions to flow inwards.