乳酸左氧氟沙星对豚鼠心肌细胞延迟整流钾电流的影响

目的:观察氟喹诺酮类药物左氧氟沙星(levofloxacin,LVFX)对豚鼠心肌细胞延迟整流钾电流(IK)的影响。方法:采用酶消化的方法分离出单个豚鼠心室肌细胞,利用全细胞膜片钳技术记录不同浓度的LVFX对豚鼠心室肌细胞IK的影响。结果:①SPX和LVFX浓度依赖地抑制IK的脉冲电流和尾电流,但不影响其原有的电压和时间依赖性。②当LVFX作用浓度分别为0.1,1,10,100,1000μM时,在+50 mV去极化电压下,测得IK的脉冲电流较对照组依次减少了(11.81±1.71)%,(14.51±2.12)%,(22.78±3.58)%,(29.59±2.89)%,(38.13±2.44)%;尾电流依次减少了(6.05±251)%,(12.19±1.49)%,(17.75±2.74)%,(30.05±1.49)%,(48.18±3.71)%。结论:LVFX在不同的浓度下对豚鼠心肌细胞的IK有不同程度的抑制。

Effect of levofloxacin lactate on delayed rectifier potassium current of guinea pig ventric ular myocytes

Objective: To study the effect of fluoroquinolone drug levofloxacin(LVFX)on delayed rectifier potassium current(IK) of guinea pig ventricular myocytes.Methods: Single guinea pig ventricular myocyte was isolated using digestive enzyme,effects of different concentrations of LVFX on delayed rectifier potassium current(IK) of guinea pig ventricular myocytes were studied using whole-cell patch clamp recording technique.Results: ①Pulse current and tail current of IK were inhibited by SPX and LVFX with concentrations dependence,but its original voltage and time-dependent were not affected.②On the condition that the concentrations of LVFX were 0.1,1,10,100,1 000 μM,and +50 mV depolarization voltage,compared with the control group for IK in this study,the pulse current reduced by(11.81 ± 1.71)%,(14.51 ± 2.12)%,(22.78 ± 3.58)%,(29.59 ± 2.89)%,(38.13 ± 2.44)%,respectively;tail current decreased by(6.05 ± 2.51)%,(12.19 ± 1.49)%,(17.75 ± 2.74) %,(30.05 ± 1.49)%,(48.18 ± 3.71)%,respectively.Conclusion: LVFX of different concentrations have different degrees of inhibitions on the delayed rectifier potassium current(IK) of guinea pig ventricular myocytes.