右美托咪定引起心动过缓的心脏电生理机制及其与钾通道的关系  

Electrophysiology mechanism of dexmedetomidine-induced bradycardia and its relationship with potassium channels

作　　者：安丽[1] 高鸿[1] 段宏伟 张凯强[3] 刘艳秋[1] 龙娟[3] 李惠[3] 钟毅[1] 

机构地区：[1]贵州医科大学附属医院麻醉科,贵阳市550004 [2]上海市浦东医院麻醉科,上海市201399 [3]贵州医科大学麻醉学系,贵阳市550004

出　　处：《实用医学杂志》2015年第21期3496-3498,共3页The Journal of Practical Medicine

基　　金：贵州省卫生计生委科学技术基金项目(编号:gzwjkj2014-1-033)

摘　　要：目的：探讨右美托咪定致心动过缓的心脏电生理机制及其与钾通道的关系。方法：成年家兔18只,体重2.0-2.5 kg,制备Langendorff离体心脏模型,K-H液平衡灌注15 min后随机分为3组（n=6）：对照组（C组）继续灌注K-H液60 min;右美托咪定组（D组）灌注含0.05μg/L右美托咪定的K-H液60 min;四乙胺组（K组）灌注含10 mmol/L四乙胺的K-H液60 min。记录平衡灌注15 min（T0）、继续灌注15、30、60 min（T1-T3）时HR、单相动作电位（MAP）,计算动作电位复极50%、90%的时程（MAPD50、MAPD90）。记录心律失常的发生情况。结果：与T0比较,D组和K组T1-T3时HR减慢（P〈0.01）,MAPD50、MAPD90延长（P〈0.05）;与C组比较,D组和K组HR减慢（P〈0.01）,MAPD50、MAPD90延长（P〈0.05）。结论：右美托咪定可能通过阻滞心肌细胞膜钾离子通道,引起动作电位时程延长,从而导致心率减慢。Objective To investigate the mechanism of dexmedetomidine-induced bradycardia on cardiac electrophysiology and its relationship with potassium channels. Methods Isolated heart perfusion models from eighteen adult rabbits, weighing 2.0 - 2.5 kg, were prepared by Langendorff and the hearts were randomly di- vided into three groups after peffusion with K-H 15 minutes （n = 6）： control group （group C, continuous perfusion 60 min）, dexmedetomidine group （group D, perfusion with 0.05 μg/L of dexmedetomidine K-H solution 60 min） and voltage-gated potassium channel blocker tetraethyla mmonium group （group K, perfusion fluid containing 10 mmol/L K-H tetraethyla mmonium）. HR, three layer myocardial monophasie action potential （MAP） of left ventrieular anterior wall after balanced infusion 15 min （T0）, continued perfusion 15, 30, 60 min （T1 - T3） were recorded. The monophasic action potential duration of repolarization at 90% and 50% were calculated respectively. The occurrence of arrhythmia were also observed. Results In group D and group K, there were slower HR （P 〈 0.01） and longer MAPD50 and MAPD90 at T1 - T3 than those at T0 （P 〈 0.05） and in Group D and group K, there were slower HR （P 〈 0.01 ） and longer MAPD50 and MAPD90 than those in group C （P 〈 0.05 ）. Conclusion Dexmedetomidine may block function of potassium channels on myocardial cell membrane, which causes the prolonging of monophasic action potential duration, resulting in slow heart beat.

关 键 词：右美托咪定 单相动作电位 钾通道阻滞剂 四乙胺 心脏 

分 类 号：R614[医药卫生—麻醉学]