甘草酸单铵对蟾蜍离体心脏功能的影响

Effects of Monoammonium Glycyrrhizinate on the Cardiac Function of Isolated Toad Hearts

目的研究甘草酸单铵对蟾蜍离体心脏的作用及其相关机制。方法采用离体蛙心灌流法观察甘草酸单铵对离体心脏的收缩力、心输出量和心率的影响。结果 1)甘草酸单铵使蟾蜍离体心脏的收缩力减弱,心输出量减少,心率略有减慢。在(0～1.5)mg.ml-1浓度范围内,甘草酸单铵抑制心肌收缩力的作用与剂量之间呈现明显的量效关系,最大效应可使心肌收缩力降低37.7%。2)随灌流液中钙离子浓度增加,甘草酸单铵对心脏的抑制作用增强;另外,甘草酸单铵的心脏抑制作用可部分被阿托品拮抗。结论甘草酸单铵可抑制蟾蜍离体心脏的功能,其作用可能与抑制细胞外的钙离子内流,减少细胞内钙有关,而与心肌细胞受体的关系有待进一步研究。

Objective To investigate the effects of monoammonium glycyrrhizinate（MAG） on the isolated toad hearts and the underlying mechanism. Methods By using isolated heart irrigation technique, the effects of MAG on the cardiac contractility, cardiac output and heart rate were investigated. Results （①MAG had the inhibitory effects on the isolated toad hearts, which could attenuate the cardiac contractility, decrease the cardiac output and reduce the heart rate. It had a obvious dose-effect rela- tionship at the concentration of （0- 1.5）mg ·mL^-1. The maximal inhibitory effect on the cardiac contractility was near 37.7 % reduction. ②The inhibition of MAG on cardiac contractility became stronger along with the increase of Ca^2＋ in the perfusion solution. Besides, the effect of MAG on the cardiac function could be partially antagonized by atropine. Conclusions MAG can inhibit the function of isolated toad hearts. The mechanism may be that MAG blocks Ca^2＋ channel on the cell membrane, and inhibit the flowing of Ca^2＋ from extracell to intercell, thus reduces the intracellular concentration of Ca^2＋ ,while the interaction of MAG and receptor on the cell membrane needs further research.