首页> 外文期刊>American Journal of Physiology >Potent block of inactivation-deficient Na+ channels by n-3 polyunsaturated fatty acids.
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Potent block of inactivation-deficient Na+ channels by n-3 polyunsaturated fatty acids.

机译:n-3多不饱和脂肪酸可有效阻断失活不足的Na +通道。

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摘要

A voltage-gated, small, persistent Na(+) current (I(Na)) has been shown in mammalian cardiomyocytes. Hypoxia potentiates the persistent I(Na) that may cause arrhythmias. In the present study, we investigated the effects of n-3 polyunsaturated fatty acids (PUFAs) on I(Na) in HEK-293t cells transfected with an inactivation-deficient mutant (L409C/A410W) of the alpha-subunit (hH1(alpha)) of human cardiac Na(+) channels (hNav1.5) plus beta(1)-subunits. Extracellular application of 5 microM eicosapentaenoic acid (EPA; C20:5n-3) significantly inhibited I(Na). The late portion of I(Na) (I(Na late), measured near the end of each pulse) was almost completely suppressed. I(Na) returned to the pretreated level after washout of EPA. The inhibitory effect of EPA on I(Na) was concentration dependent, with IC(50) values of 4.0 +/- 0.4 microM for I(Na) peak (I(Na peak)) and 0.9 +/- 0.1 microM for I(Na late). EPA shifted the steady-state inactivation of I(Na peak) by -19 mV in the hyperpolarizing direction. EPA accelerated the process of resting inactivation of the mutant channel and delayed the recovery of the mutated Na(+) channel from resting inactivation. Other polyunsaturated fatty acids, docosahexaenoic acid, linolenic acid, arachidonic acid, and linoleic acid, all at 5 microM concentration, also significantly inhibited I(Na). In contrast, the monounsaturated fatty acid oleic acid or the saturated fatty acids stearic acid and palmitic acid at 5 microM concentration had no effect on I(Na). Our data demonstrate that the double mutations at the 409 and 410 sites in the D1-S6 region of hH1(alpha) induce inactivation-deficient I(Na) and that n-3 PUFAs inhibit mutant I(Na).
机译:在哺乳动物的心肌细胞中已显示出电压门控的持久性小Na(+)电流(I(Na))。低氧增强了可能导致心律不齐的持续性I(Na)。在本研究中,我们研究了n-3多不饱和脂肪酸(PUFAs)对转染有α-亚基(hH1(alpha)的失活缺陷型突变体(L409C / A410W)的HEK-293t细胞中I(Na)的影响))人的心脏Na(+)通道(hNav1.5)加上beta(1)-亚基。在细胞外应用5 microM二十碳五烯酸(EPA; C20:5n-3)可以显着抑制I(Na)。 I(Na)的后期部分(I(Na late),在每个脉冲结束时测得)几乎完全被抑制。 EPA洗脱后,I(Na)恢复至预处理水平。 EPA对I(Na)的抑制作用与浓度有关,IC(50)的I(Na)峰(I(Na峰))值为4.0 +/- 0.4 microM,I(Na峰)为0.9 +/- 0.1 microM。娜(晚)。 EPA将I(Na峰)的稳态失活在超极化方向上移动了-19 mV。 EPA加速了静态通道失活的静止过程,并延迟了静态通道失活的Na(+)突变通道的恢复。其他多不饱和脂肪酸,二十二碳六烯酸,亚麻酸,花生四烯酸和亚油酸都为5 microM浓度,也能显着抑制I(Na)。相反,浓度为5 microM的单不饱和脂肪酸油酸或饱和脂肪酸硬脂酸和棕榈酸对I(Na)没有影响。我们的数据表明,在hH1α的D1-S6区域中的409和410位的双重突变诱导了失活缺陷的I(Na),而n-3 PUFA抑制了突变的I(Na)。

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