The dihydropyridine niguldipine modulates calcium and potassium currents in vascular smooth muscle cells
The dihydropyridine niguldipine modulates calcium and potassium currents in vascular smooth muscle cells
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二氢吡啶尼古地平调节血管平滑肌细胞中的钙电流和钾电流
DOI：
10.1111/j.1476-5381.1989.tb12037.x
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发表时间：
1989
影响因子：
7.3
通讯作者：
G. Isenberg
中科院分区：
文献类型：
--
作者：
U. Klöckner;G. Isenberg
1从牛门静脉和软脑膜血管分离血管平滑肌细胞。用单片电极技术(全细胞记录)进行电压钳制，以分析尼古地平对离子膜电流的影响。由于尼古地平在塑料和玻璃上的吸附，其有效浓度比标称浓度低约3.2倍。2尼古地平在标称浓度>；0.1μm时降低钙电流(L型，电压操作)，直到1μm时完全阻断(0.4μm时50%阻断)。标称浓度在50到200 nm之间有利于ICA(“钙激动剂效应”)。尼古地平的钙兴奋作用表现出适度的使用--但强烈的电压依赖性。3尼古地平在标称浓度>；10 nm时增加外向电流。在−为85 mV时，额外的外向电流发生逆转，提示尼古地平使钾电流Ik增加。尼古地平的最大促进率约为400%，在1μm时达到最大促进率，标称浓度为20 nm时达到半最大促通率。4尼古地平降低ICA和易化IK可能参与了尼古地平的血管扩张作用。由于其更高的敏感度，对IK的影响可能占主导地位。
1 Vascular smooth muscle cells were isolated from the portal vein and from pial vessels of the cow. They were voltage‐clamped with a single patch electrode technique (whole cell recording) in order to analyse the effects of niguldipine on ionic membrane currents. Due to adsorption of niguldipine to plastic and glass, the effective concentrations are lower than the nominal concentrations by a factor of about 3. 2 Niguldipine reduced Ca‐currents (ICa of the L‐type, voltage operated) at nominal concentrations > 0.1 μm up to a complete block at 1 μm (50% block at 0.4 μm). Nominal concentrations between 50 and 200 nm facilitated ICa (‘Ca‐agonistic effect’). The Ca‐agonistic effects of niguldipine showed modest use‐ but strong voltage‐dependence. 3 Niguldipine increased the outward currents at nominal concentrations >10nM. The extra outward currents reversed at −85 mV, the result suggesting that niguldipine had increased potassium currents, IK. Maximal facilitation of IK by niguldipine was about 400% and was obtained at 1 μm, half‐maximal facilitation was obtained with a nominal concentration of 20 nm. 4 Both reduction of ICa and facilitation of IK may contribute to vasodilatation by niguldipine. Due to its greater sensitivity, the effects on IK may dominate.