ω-3多不饱和脂肪酸对大鼠心室肌细胞动作电位的影响

目的探讨ω-3多不饱和脂肪酸对大鼠心室肌细胞动作电位（AP）的影响。方法①在自制心脏灌流装置上，采用三步法行逆行主动脉灌流获得单个耐钙心肌细胞；②以全细胞膜片钳技术分别记录加入10、20、40、60、80、100、120和200μmol·L^-1ω-3多不饱和脂肪酸二十二碳六稀酸（DHA）后大鼠心室肌细胞AP的变化。结果成功记录到大鼠心室肌细胞外膜、中膜和内膜AP。外膜、中膜和内膜心室肌细胞动作电位时程（APD）逐渐延长（P〈0．05），其中外膜APD25、APD50和APD50分别为（3．6±1．2）ms、（10．3±2．1）ms和（46．3±4．8）ms；中膜分别为（6．4±1.8）ms、（14．7±2．4）ms和（69．4±8．3）ms；内膜分别为（13．8±2．1）ms、（45．3±10．2）ms和（152．1±33．4）ms；②DHA浓度在0～30μmol·L^-1时，随着DHA浓度增加，APD延长不明显（P〉0．05）；当DHA浓度大于30μmol·L^-1时，APD逐渐延长，且呈浓度依赖性（P〈0．05）。结论大鼠外膜、中膜和内膜心室肌细胞AP形态存在分层差别，ω-3多不饱和脂肪酸DHA对AP的影响可能是其抗心律失常作用机制之一。

Effects of ω-3 Polyunsaturated Fatty Acid on Action Potential of Rat Ventricular Myocytes

Objective To investigate effects ofdocosahexaenic acid （DHA） of ω-3 polyunsaturated fatty acid （ω-3 PUFA） on action potential （AP） of rat ventrieular myocytes. Methods ①Calcium-tolerant ventricular myocytes were obtained by three-step retrograde perfusate with perfusing apparatus made by ourselves. ②Changes of AP with DHA of to-3 PUFA at 10, 20, 40, 60, 80, 100, 120 and 200 μmol·L^-1 were recorded respectively by whole-cell patch clamp configuration. Results ①APs were successfully recorded by whole-cell patch clamp configuration. Action potential durations （APDs） were gradually prolonged from epicardial to endocardial ventricular myocytes. APD25, APD50 and APD50 of epicardial, mid-cardial and endocardial myocytes were （3.6±1.2ms, 10.3±2.1ms, 46.3±4.8ms）; （6.4±1.8ms, 14.73±2.4ms, 69.4±8.3 ms） and （13.8±2.1ms, 45.3±10.2ms, 152. 1±33.4 ms） respectively. There were significant differences （P〈0.05）. ②APDs were gradually prolonged with the increase of DHA from 30 to 200μmol·L^-1, while APD changes were not significant from 0 to 30μmol·L^-1（P〉 0.05）. Conclusion There are regional differences in the distribution of AP in rat epicardial, mid-cardial and endocardial ventricular myocytes. Effects of DHA of ω-3 PUFA on AP may be one of mechanisms of antiarrhythmia.