亚麻酸对心力衰竭人心房肌细胞瞬时外向钾电流的影响

探讨亚麻酸对心力衰竭病人心房肌细胞瞬时外向钾电流 (Ito)的作用。应用膜片钳全细胞记录技术 ,记录细胞外应用亚麻酸 (十八碳二烯酸 )前后人心房肌细胞Ito。结果表明 :①亚麻酸对人心房肌细胞的Ito抑制作用表现为浓度依赖性 ,2 .5 ,5及 10 μmol/L的抑制率分别为 16 %± 4%、2 8%± 6 %和 5 1%± 6 % (P <0 .0 5 ) ,但无频率依赖性。②用药前后Ito的激活曲线几乎重叠 ,5 0 %的通道激活电压分别为 19.5± 1.7和 17.6± 1.4mV(P >0 .0 5 ) ;用药后的电流失活曲线左移 ,V1/2 电压为 - 33.3± 2 .4和 - 44 .4± 3.1mV ,即左移 11.2± 1.2mV(P <0 .0 1)。③Ito恢复 5 0 %的时间延长 ,即从 39.3± 3.4到 85 .1± 5 .8ms(P <0 .0 1)。结论 :亚麻酸对心力衰竭病人心房肌细胞Ito具有抑制作用 ,延长该通道的恢复时间

Effects of Linolenic Acid on Transient Outward Current in Atrial Myocytes From Patients With Heart Failure.

To explore the effects of linolenic acid(LNA,C18:3 n 3)on transient outward current(I to ) in atrial myocytes from patients with heart failure.Patch clamp technique was used to record I to in atrial myocytes from patients with heart failure before and after administration of extracellular LNA.Results:①The LNA induced suppression of I to current shown dose dependent and frequency independent.The I to inhibition percent of 2.5,5 and 10 μmol/L LNA respectively were 16%±4%,28%±6% and 51%±6%( P<0.05 ),②The activation curves from relative conductance in the absence and presence of LNA(5 μmol/L)almost overlapped.The 50% channel activation was at 18.2±1.7 and 17.0±1.8 mV in the absence and presence of 5 μmol/L LNA resepectively( P>0.05 ).Steady state inactivation curve shifted to left from -32.8±2.6 to -45.4±3.4 mV significantly,in the absence and presence of 5 μmol/L at V 1/2 point( P<0.01 ).③The time for 50% recovery delayed from 39.3±3.4 to 85.1±5.8 ms significantly in the absence and presence of 5 μmol/L LNA( P<0.01 ).Conclusions:The present data demonstrated that linolenic acid suppressed I to and prolonged the duration of recovery from inactivation in atrial myocytes from patients with heart failure.