盐酸雷诺秦对豚鼠乳头肌动作电位及收缩力的影响

目的通过盐酸雷诺秦对离体豚鼠心室乳头肌动作电位及收缩力的影响,探讨其抗心律失常及心肌缺血的机制。方法健康成年豚鼠18只,随机分为H2O2(200 mmol.L-1)组、雷诺嗪(10 mmol.L-1)+H2O2组和TTX(2 mmol.L-1)+H2O2组,每组6只,采用给药前后自身对照的方法观察雷诺秦对豚鼠乳头肌的作用。结果H2O2可使对照组动作电位APD50、APD90明显增加(P0.001),心肌收缩力降低(P0.05),雷诺嗪可抑制H2O2引起的动作电位时程APD50、APD90的延长(P0.05和P0.01),但作用弱于TTX(P0.05和P0.001),雷诺嗪、TTX可改善H2O2引起的心肌收缩力降低。结论盐酸雷诺嗪可降低H2O2引起的豚鼠乳头肌动作电位动时程的增加和增强心肌收缩力,作用和TTX结果相似。

Effects of ranolazine on action potential and contraction force in guinea pig papillary muscles

Objective To observe the effects of ranolazine on the action potential and contraction force in guinea pig papillary muscles, Explore the mechanism of ranolazine anti-arrhythmia and myocardial ischemia. Methods Eighteen healthy adult guinea-pigs were randomly divided into H2O2 （ 200 mmol ·L^- 1 ） groups, ranolazine （ 10 mmol · L^- 1 ） ＋ H2O2 groups and TIX（ 2 mmol · L^- 1 ） ＋ H2O2 groups, with six guinea pigs in every group compared with themselves before administration to observe the effects of ranolazine on the papillary muscles. Results H2O2 could increase action potential durations measured at the 50% repolarization levels and the 90% repolarization levels were prolonged（ P 〈 0.001 ）, Reduced myocardial contractility（ P 〈 0.05） compared with before administation contraction force in guinea pigs compared with themselves before, Ranolazine can inhibit action potential durations measured at the 50% repolarization levels and the 90% repolarization levels were prolonged of H2O2, But the effect was weaker than Trx, Ranolazine and TTX could improve myocardial contractile force to reduce the H202-induced. Conclusion ranolazine could reduce action potential duration the H2O2-induced and increase contraction force. Similar to the role and TTX.