硒对大鼠心电图及心肌细胞动作电位的影响

目的　探讨硒对大鼠心电图及心肌细胞动作电位的影响。方法　对Ｗ ｉｓｔａｒ雄性大鼠腹腔内注射亚硒酸钠（２ｍ ｇ·ｋｇ－１·ｄ－１），连续９ 周，应用心电图和细胞内玻璃微电极技术，观察正常大鼠和阿霉素致心肌损伤大鼠心电图及心肌细胞动作电位的变化。结果　硒组心电图较实验前及对照组无变化（ Ｐ ＞ ０．０５ ），心肌细胞复极达峰值电位５０％ 所需时间（ＡＰＤ５０）延长（ Ｐ ＜ ０．０５ ）。ＡＤＭ 组和硒＋ ＡＤＭ 组心电图Ｑ－Ｔ 间期及心肌细胞ＡＰＤ５０、ＡＰＤ９０较对照组及试验前均延长（ Ｐ＜ ０．０１）。心率、静息电位（ＲＰ）、动作电位幅度（ＡＰＡ）及动作电位０ 相最大去极化速率（Ｖｍ ａｘ）无变化（ Ｐ ＞ ０．０５）。结论　硒能延长正常大鼠心肌细胞ＡＰＤ５０，不能逆转阿霉素心肌损伤大鼠ＡＰＤ５０、ＡＰＤ９０及Ｑ—Ｔ 间期延长。此结果对于心肌病的防治具有重要意义。

Effects of selenium on electrocardiogram and action potential in rats

Objective To understand effects of selenium (Se) on the electrocardiogram (ECG) and action potential (AP) in rats.Methods Wistar rats were given intraabdominal injection of Se (0.02mg.kg 1 ) once daily for 2 weeks and every other day for 7 weeks.After injection of Se the changes of Q_T interval and AP in healthy rats and rats with cardiomyopathy of adriamycin (ADM) were observed with ECG and the technique of intracelluar glass microelectrode recording.Results The action potential duration (APD 50 ) of ventricular papillary muscle was prolonged (P<0.05) but Q-T interval of ECG was not changed in healthy rats after injection of Se.Both Q-T interval and APD(APD 50 ,APD 90 ) were all prolonged (P<0.05~0.01) in rats with cardiomyopathy of ADM after injection of Se.Se had no effects of the heart rate,restiong potential (RP),amplitude of action potential (APA) and the maximum depolarization rate of AP (Vmax).Conclusions Se could prolong APD 50 but could not affect clearly Q-T interval in healthy rats.Se could not reverse changes of APD(APD 50 ,APD 90 ) and Q-T interval in rats with cardiomyopathy of ADM.The results are very significant for provention and treatment of cardiomyopathy.