异丙酚对兔心室M细胞和外膜层心肌细胞动作电位特性的影响

Effect of propofol on the electrophysiological characteristics of the action potential generated by myocardial and epicardial cells in rabbits

目的评价异丙酚对兔心室M细胞及外膜层心肌细胞动作电位特性的影响。方法新西兰大耳白兔48只，体重2～3k，经3％戊巴比妥钠30mg／kg麻醉后建立离体心脏灌注模型，随机分为3组（n=16），对照组（C组）持续灌注标准台氏液；不同浓度异丙酚组（P1组和R组）分别灌注含异丙酚10、50μmol／L的标准台氏液。三组均于标准台氏液平衡灌注60min时，应用传统玻璃微电极技术测定M细胞及外膜层心肌细胞静息膜电位（RMP）、动作电位幅值（APA）和动作电位复极90％的时程（APD90），计算心室复极离散度（TDR）为基础值，异丙酚持续灌注60min后测定M细胞及外膜层心肌细胞上述参数，计算TDR。结果三组心室M细胞及外膜层心肌细胞的RMP和动作电位参数基础值差异无统计学意义（P〉0．05）；与C组比较，P1组和P2组心肌持续灌注期间心室M细胞及外膜层心肌细胞APD90缩短，P2组TDR降低（P〈0．05），P1组TDR差异无统计学意义（P〉0．05）；与P1组比较，P2组心室M细胞及外膜层心肌细胞APD90缩短，TDR降低（P〈0．05），RMP及APA比较差异无统计学意义（P〉0．05）。结论异丙酚可缩短心室M细胞和外膜层心肌细胞动作电位时程，但不增加复极离散度，对心电活动具有一定的稳定效应。

Objective To investigate the effect of propofol on the electrophysiological characteristics of the action potential generated by myocardial and epieardial cells in the isolated arterially perfused rabbit ventrieular wall. Methods Forty-eight adult New Zealand long-ear white rabbits weighing 2-3 kg were anesthetized with intraperitoneal 3% pentobarbital sodium 30 mg/kg. The chests were opened and the hearts were excised. A piece of wedge-shaped anterior wall of left ventricle （0.8 cm× 0.5 cm × 0.4 cm） with its perfusing artery was obtained from each heart. The ventrieular wedge preparations were randomly divided into 3 groups （ n = 16 each） ： control group （C） was perfused with Tyrode solution and 2 propofol groups were perfused with 10 μmol/L and 50 μmol/L propofol respectively （P, and P2 ）. After 60 rain of equilibration the baseline of rest membrane potential （RMP）, amptitude of action potential （APA）, 90 % repolarization of action potential （APDgo） and transmural dispersion of repolarization （TDR） were simultaneously recorded from the ventrieular myocardium and epicardium using the classic microeleetrode technique. After perfusion with propofol solution for 60 min, the RMP, APA, APD90 and TDR were recorded again. Results There were no significant differences in the baseline of RMP, APA, APDgo and TDR among the 3 groups. APD90 was significantly lower in group P1 and P2 than in group C. TDR was significantly decreased in group P2 as compared with group C. APD90 and TDR were significantly decreased in group P2 as compared with group P1 , but there was no significant change in RMP and APA after propofol perfusion.Conclusion Propofol can reduce the duration of action potential generated by ventricular myocardium and epicardium, but does not increase TDR, resulting in the stabilization of cardiac electric stability.