四氢巴马汀对家犬在体心脏单相动作电位和有效不应期影响的研究

利用单相动作电位 (MAP)技术 ,研究在整体条件下四氢巴马汀 (THP)对家犬在体心脏MAP和有效不应期(ERP)的影响 ,从而探讨THP在整体条件下的抗心律失常机制。家犬 8只 ,体重 12 .5± 3.0 ( 10～ 15 )kg。同时记录家犬右室心尖部的MAP和体表Ⅱ导联心电图 (ECG) ,比较在窦性心律下用药前和用药后 10 ,2 0 ,30min的ERP、MAP复极 5 0 %时程 (MAPD5 0 )和复极 90 %时程 (MAPD90 )以及MAP振幅 (MAPA)的变化。结果 :用药后 10min ,各参数均无明显变化 (P >0 .0 5 ) ;用药 2 0min后 ,ERP、MAPD5 0 和MAPD90 与用药前相比 ,均明显延长 (分别为 139± 18msvs 12 4±18ms,12 6± 16msvs112± 15ms ,16 4± 2 5msvs 140± 16ms,P均 <0 .0 1) ,但用药前后ERP MAPD90 的比值无显著性变化 (P >0 .0 5 )。结论 :THP通过延长动作电位 2相和 3相时程 ,使ERP和MAPD90 平行延长 ,但不改变用药前后ERP MAPD90 比值 ,从而具有增加心肌电稳定性的作用 ,推测此是其具有抗室性心律失常的作用的可能机制

Effects of Tetrahydropalmatine on Monophasic Action Potential and Effective Refractory Period in the Dog Heart

In 8 Canines,monophasic action potential (MAP) were recorded from the tip of right ventricular before and after tetrahydropalmatine (THP) adminnistration.The duration of MAP at 50% (MAPD 50 ) and 90% (MAPD 90 ) repolarization,amplitude of MAP (MAPA) and effective refractory period (ERP) were measured during sinus rhythm.The changes of ERP,MAPA and MAP duration were assessed at 10,20, and 30 minutes after administration of intravenous THP 10,15,20 mg/kg.At 10 minutes after administration of the drug,THP had no effect on ERP,MAPD 50 and MAPD 90 (P>0.05).After 20 minutes,the ERP,MAPD 50 and MAPD 90 were significantly prolonged (139±18 mV vs 124±18 mV,126±16 ms vs 112±15 ms,164±25 ms vs 140±16 ms,respectively,P<0.01) compared with that before the administration of THP but unchanged the ratio of ERP to MAPD 90 (P>0.05).There was no apparent effect on MAPA (P>0.05).Conclusion:THP parallelly prolonged ERP and MAPD 90 ,but didn't change the ratio of ERP to MAPD 90 ,then it had effect on antiarrhythmia through increasing the electric stability of cardiomyocyte.Chinese Journal of Cardiac Pacing and Elecgtrophysiology,2000,14(2):121～123]. Tetrahydropalmatine Monophasic action potential Effective refractory period Dog