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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 observe the effect of Cordyceps Cephalosporium Mycelia (CCM) extract on the action potentials of guinea pig papillary muscle obtained by modified technique and to explore the mechanism of experimental antiarrhythmic effect of CCM extract. Methods The rat model of ischemic arrhythmia induced by pituitrin was used to observe the change of electrocardiogram before and after treatment. Guinea pig papillary muscle transmembrane action potential (TAP) was recorded using standard glass microelectrode technique. The effects of different concentrations of CCM extract (10, 30, 100 mg.L 1) on myocardial TAP of standard Tyrode fluid were observed under the stimulation of 1.0 Hz. Results After the tail vein was injected with Pit, the amplitude of T wave in ECG changed bidirectionally. The CCM extract could significantly reduce the influence of Pit on T wave and reduce the incidence of pit-induced arrhythmia. CCM extracts at different concentrations could decrease the action potential amplitude (APA) and the maximal rate of 0 phase increase (Vmax) in a concentration-dependent manner; 50% and 90% (APD50, APD90) Interest rate (RP) no significant effect. Conclusions The inhibition of APA and Vmax and the prolongation of APD in ventricular myocardium by modified CCM may be the electrophysiological basis of anti-arrhythmic effect.