改良技术虫草头孢菌粉提取物对缺血性心律失常和心肌细胞动作电位的影响

Effects of Cordyceps Cephalosporium Mycelia Extracts on Myocardial Ischemia and Transmenbrance Action Potential of Ventricle Myocytes

目的观察采用改良技术获得的虫草头孢菌粉(Cordyceps Cephalosporium Mycelia,CCM)提取物对豚鼠乳头肌动作电位的影响,探讨CCM提取物实验性抗室性心律失常的机制。方法利用垂体后叶素(Pit)诱发的大鼠缺血性心律失常模型,观察用药前后心电图的改变。采用标准玻璃微电极技术,记录豚鼠乳头肌跨膜动作电位(TAP)。在频率为1.0 Hz刺激下,观察不同浓度的CCM提取物(10,30,100 mg.L 1)对标准Tyrode液灌流心肌TAP的影响。结果大鼠在尾静脉注射Pit后,其心电图T波波幅发生双向性改变,CCM提取物可明显减弱Pit对T波的影响,并降低Pit诱导的心律失常发生率。不同浓度的CCM提取物可浓度依赖性地降低动作电位幅度(APA)以及0相最大上升速率(Vmax);可延长动作电位复极50%和90%的时间(APD50、APD90);但对静息电位(RP)无明显影响。结论改良技术获得的CCM对APA和Vmax的抑制及对心室肌APD的延长可能是其抗心律失常作用的电生理基础。

OBJECTIVE To investigate the effect of Cordyceps Cephalosporium Mycelia （CCM） extracts on electrophysiological characteristic of endocardium from guinea pig ventricle, and explore its mechanism aganist arrhythmia. METHODS The ECG was recorded in rat suffered from pituitrin-induced myocardial ischemia. Standard microelectrode technique was used to record the transmembrane action potential of endocardium of guinea pig ventricular myocytes. And the effect of CCM extracts of different concentrations on action potential duration （APD） of endocardium at basic sitmulate 1.0 Hz was evaluated. RESULTS The CCM extracts significantly inhibited changes of T wave in ECG, and reduced the incidence rate of arrhythmia induced by pituitrin. The CCM extracts delayed the amplitude of action potential （APA） and maximal velocity （Vmax）, and prolonged the APD50 and APD90 in a dose-dependent manner in guinea pig. The CCM extracts had no effect on resting potential （RP）. CONCLUSION The CCM extracts could protect against pituitrin-induced antiarrhythmia, the mechanism might be involved in inhibition of APA and Vmax and prolonging APD50 and APD90.