脂布福吉宁和乙酰毒毛花甙诱发离体浦肯野氏纤维延时性后去极化及触发性心律失常的比较(英文)

Induction of delayed afterdepolarizations and triggered arrhythmias in isolated Purkinje fibers: comparison of resibufogenin and acetylstrophanthidin

用细胞外电图信号叠加技术微电极,于羊浦肯野纤维上,比较脂布福吉宁(RBG)(?)乙酰毒毛花甙元(AS)对诱发延时性后去极化(DAD)和触发性心律失常(TA)的作用,结果:1)低中毒剂量于刺激为990和690 ms时诱发出胞内和胞外的DAD;2)高中毒剂量诱发出DAD及TA,包含过早动作电位及触发性心动过速等;3)均引起动作电位振幅、静息电位及最大舒张期电位的降低、50％APD及Q-T间期的缩短,故RBG属于洋地黄类药物。

The purpose of this study was to compare the electrotoxicological effects of resi-bufogenin (RBG) (n = 14) with acetylstro-phanthidin (AS) (n=14) to induce delayed af-terdepolarization (DAD) and triggered activity (TA), and their alteration of the electrophysi-ological properties in sheep cardiac Purkinje fibers using the extracellular electrograms, .signal averaging, and standard microelectrode techniques simultaneously. The results indicated: 1) Lower toxic dose of RBG (0.52 μmol · L-1) and AS (0.25 μmol · L-1) induced intracellular and extracellular DAD (DAD-I and DAD-E) at pacing cycle length of 990 and 690 ms. 2) Higher toxic dose of RBG (2. 6 μmol · L-1) and AS (5. 0 μmol · L-1) induced DAD and TA, nonsustained or sustained premature action potential and oscillatory potentials; 3) At the beginning period of superfusing the drugs, both RBG and AS caused changes of the electrophysiological characteristics. This study demonstrates that the electro-toxicological characteristics and electrophysiological properties of RBG are similar to that of AS and suggests that RBG belongs to the family of digitalis-like drugs.