枸骨叶水提物对蟾蜍心肌收缩力的影响及其机制初探

Effects of aqueous extract from leaves of Ilex cornuta Lindl on myocardial contractility of toad and the underlying mechanisms

目的 研究枸骨叶水提物对蟾蜍心肌收缩力的影响及其机制。方法 采用煎煮法制备枸骨叶水提物。采用蛙心灌流法和BL-420E智能生物信号采集与处理系统,观察不同浓度枸骨叶水提物对离体蟾蜍心肌收缩力的作用、枸骨叶水提物对肾上腺素刺激以及不同钙离子浓度灌流条件下心肌收缩力的影响。结果 枸骨叶水提物在0.1~1.6mg/ml浓度范围内剂量依赖性抑制蟾蜍基础条件下心肌收缩力,最大效应可使心肌收缩力降低55.12%;枸骨叶水提物对肾上腺素刺激条件下蟾蜍心肌收缩力亦有显著抑制作用,0.4mg/ml枸骨叶水提物即可完全阻断肾上腺素的兴奋作用;枸骨叶水提物在不同钙离子浓度任氏液灌流条件下抑制率保持稳定,约为20%。结论 枸骨叶水提物对基础条件下以及肾上腺素刺激条件下蟾蜍心肌收缩力均有显著抑制作用,其抑制率与浓度相关,与细胞外钙离子浓度无关,其作用机制可能与抑制心肌细胞β受体有关。

Objective To investigate the mechanism and effects of aqueous extract from leaves of Ilex cor- nuta Lindl on myocardial contractility of toad. Methods The method of decoction was adopted to prepare the aqueous extract from leaves of Ilex cornuta Lindl. By isolated frog heart perfusion and BL-420E data acquisition and analysis system the effects of different concentrations of aqueous extract on myocardial contractility were investigated under basal condition, epinephrine stimulated condition or different [ Ca2 ＋ ] ringer＇s solution perfusi0n condition. Results Aqueous extract from leaves of Ilex cornuta IAndl could inhibit cardiac contractility,which had an obvious dose-effect relationship within the concentration from 0. 1 mg/ml tol. 6mg/ ml,and the maximal inhibitory rate was 55.12%. The excitatory effect of epinephrine on cardiac contractility could be significantly antagonized by aqueous extract,and 0.4mg/ml aqueous extract,a relatively small dose, could completely block the effect of epinephrine （ 0.1μg/rnl ）. The inhibition rate of the aqueous extract was about 20% , even with the changed [ Ca2 ＋ ] in the perfusion solution. Conclusion Aqueous extract from leav- es of Ilex cornuta Lindl could inhibit the cardiac contractility in basal and epinephrine stimulated condition in an dose-dependent manner,which was uninfluenced by [ Ca2＋ ] in the perfusion. The mechanism might be related to inhibiting B-receptors on hearts.