同步监测蟾蜍心脏机械和电活动简便而有效的方法

目的: 通过灌流蟾蜍离体原位自发性搏动心脏,同步监测心输出量、心肌收缩力和心电图的变化,为研究心脏活动探索简便、有效和经济的实验方法。方法: 在离体原位心脏左主动脉和后腔静脉插管回流,记录心输出量;在心尖部连接张力换能器,肢体皮下插入针状电极,利用BL-420S生物机能实验系统监测心肌舒缩张力和标准肢体II导联心电图。通过灌注β受体激动药异丙肾上腺素和其拮抗药普萘洛尔,观察各参数的变化,证实该实验方法的可行性。结果: 在灌注任氏液的条件下,能够很好地监测到心脏舒缩张力和心输出量,以及心电图PR间期、QT间期、QRS波群时间和电压,适于分析二者之间的相关性。与给药前相比较,灌注10^-5~10^-4 g/L异丙肾上腺素显著增加了心输出量和心肌舒缩幅度,缩短了心电图PR间期,延长了QT间期(P<0.05, P<0.01)。灌注普萘洛尔能够明显拮抗异丙肾上腺素的强心作用。结论: 本实验方法适于同时监测蟾蜍心脏的收缩能力和心电图。

Simple and effective method for simultaneously detecting the cardiac contractility and electrocardiogram in toads

AIM: To investigate a simple,effective and economic method suitable for simultaneously monitoring the contractility and electrocardiogram(ECG) of the in situ spontaneously beating toad hearts. METHODS: The perfusate was circulated by cannulating in the postcaval vein for inflow and the left branch of the arterial trunk for outflow to detect the cardiac output.Meanwhile,the force transducer was attached on the apex of the heart,and the standard limb lead Ⅱ was applied to monitor the force and ECG with the BL-420S data acquisition and analysis system.Isoproterenol,a β-adrenoceptor agonist,and its antagonist propranolol,were perfused to confirm the feasibility of the method. RESULTS: When perfused with Ringer’s solution,the cardiac output and force were readily detected,and the PR interval,QT interval,and width and amplitude of QRS waves were clear,which was suitable for analyzing the relationship between them.Compared to pretreatment,perfusion of isoproterenol at concentrations of 10-5~10-4 g/L significantly increased the cardiac output and force,shortened PR interval,and prolonged QT interval(P<0.05,P<0.01).Propranolol antagonized the positive inotropic effect of isoproterenol. CONCLUSION: This method is suitable for simultaneously detecting the cardiac contractility and ECG in toads.