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.
出处
《实用医学杂志》
CAS
北大核心
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)
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
Dexmedetomidine
Monophonic action potential
Potassium channel blockers
Tetraethylammonium
Heart
