钾通道在瑞芬太尼延长家兔心肌单相动作电位时程中的作用

Role of potassium channel in remifentanil-induced prolongation of monophasic action potential duration in myocardium of rabbits

目的探讨钾通道在瑞芬太尼延长家兔心肌单相动作电位时程中的作用。方法成年家兔，成功制备Langendorff离体心脏灌注模型18个，采用随机数字表法，将其分为3组（n=6）：对照组（C组）、瑞芬太尼组（R组）和钾通道阻滞剂四乙胺组（T组）。平衡灌注15min时C组继续灌注K—H液60min；R组和T组分别灌注含12ng／ml瑞芬太尼和10ng／ml四乙铵的K—H液60min。记录平衡灌注15min、继续灌注15、30、60min时HR、左心室前壁三层心肌单相动作电位，计算单相动作电位复极50％和90％的时程（MAPD50、MAPD90）。结果与C组比较，R组和T组继续灌注15、30、60min时HR减慢，MAPD50和MAPD90延长（P〈0．05）。结论瑞芬太尼延长家兔心肌单相动作电位时程的机制与阻滞钾通道有关。

Objective To investigate the role of potassium channel in remifentanil-induced prolongation of monophasic action potential duration （MAPD） in the myocardium of rabbits. Methods Eighteen adult rabbit hearts successfully perfused in a Langendorff apparatus were randomly divided into 3 groups （ n= 6 each） using a random number table： control group （ group C） , remifentanil group （ group R） , and K＋ channel blocker tetraethylammonium group （group T）. After 15 min stabilization with K-H solution, group C was continuously perfused with K-H solution for 60 min, and R and T groups were perfused with K- H solution containing 12 ng/ml remifentanil and 10 ng/ml tetraetbylammonium, respectively, for 60 min. At 15 min of stabilization, and 15, 30 and 60 min of perfusion, heart rate, MAPD of all the three layers of the myocardium in the anterior wail of the left ventricular was recorded. MAPD at 50% and 90% repolarization （MAPDs0, MAPDg0） were calculated. Results Compared with group C, heart rate was significantly decreased, MAPD50 and MAPD90 were prolonged in R and T groups （P 〈0.05）. Conclusion The mechanism by which remifentanil prolongs MAPD in the myocardium of rabbits is associated with blockade of the potassium channels.