COMPARISON OF CA-2+-DEPENDENT K+ CHANNELS IN THE MEMBRANE OF SMOOTH-MUSCLE CELLS ISOLATED FROM ADULT AND FETAL HUMAN AORTA
COMPARISON OF CA-2+-DEPENDENT K+ CHANNELS IN THE MEMBRANE OF SMOOTH-MUSCLE CELLS ISOLATED FROM ADULT AND FETAL HUMAN AORTA
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DOI：
10.1007/bf00581222
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发表时间：
1988-11-01
影响因子：
4.5
通讯作者：
ZAMOYSKI, V
中科院分区：
文献类型：
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作者：
BREGESTOVSKI, PD;PRINTSEVA, OY;ZAMOYSKI, V
采用全细胞和单通道膜片钳技术研究了Ca2+激活的K+离子电流在培养的胎儿和成人主动脉平滑肌细胞膜中的作用。成人平滑肌细胞的全细胞电流比同等大小的胎儿细胞大3-8倍。在两种类型的细胞中，单个Ca2+活化的K+的基本电导和离子选择性是相同的。通道开口发生破裂，其持续时间在成人细胞比胎儿细胞长3-5倍。通道激活机制的电压依赖性和平均打开时间对膜内侧Ca2+浓度的依赖性在两种类型的细胞中是相似的。这些结果表明，发育过程中钾电导增加的主要原因是Ca2+激活的K+通道开放时间的改变。
Ca2+-activated K+ ionic currents in the membrane of cultured smooth muscle cells isolated from foetal and adult human aorta were studied using whole cell and single-channel patch-clamp techniques. Whole cell currents in adult smooth muscle cells were 3-8 times larger than in foetal cells of similar sizes. The elementary conductance and ionic selectivity of single Ca2+-activated K+ were identical for both types of cells. Channel openings occurred in burst, the duration of which was 3-5-fold longer in adult than in foetal cells. The voltage dependency of the channel activating mechanism and the dependency of the mean open time on the Ca2+ concentration on the inner side of the membrane were similar for both types of cells. These results suggest that the main reason for the increase in potassium conductance during development is an alteration in the open time of the Ca2+-activated K+ channels.