Expression of cyclic nucleotide-gated cation channels in airway epithelial cells.
Expression of cyclic nucleotide-gated cation channels in airway epithelial cells.
复制标题
气道上皮细胞中环核苷酸门控阳离子通道的表达。
DOI：
10.1007/s002329900564
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Guggino,SE
中科院分区：
文献类型：
--
作者：
Xu,W;Leung,S;Wright,J;Guggino,SE
使用全细胞膜片钳技术，比较了人肺泡细胞系A549中8-Br-cGMP刺激电流与转染hα CNC 1的HK 293细胞中8-Br-cGMP刺激电流的选择性和药理学。在转染hα CNC 1或A549的HK 293细胞中，8-Br-cGMP刺激的全细胞电流均由内向钠和外向钾携带，选择性几乎相同。在转染hα CNC 1的HK 293细胞上，8-Br-cGMP刺激的全细胞内向电流被1-cis-diltiazem抑制，IC 50为154 μm，被2′，4 ′-dichlorobenzamil抑制，IC 50为50 μ m，被amiloride抑制，IC 50为133 μm。8-Br-cGMP刺激的A549细胞的全细胞内向电流被1-cis-diltiazem抑制，IC_（50）为87 μm，被2′4′-dichlorobenzamil抑制，IC_（50）为38 μ m，被amiloride抑制，IC_（50）为32 μ m，提示这些气道细胞含有环核苷酸门控阳离子通道。RT-PCR数据表明，α CNC 1和βCNC亚基的mRNA都存在于A549细胞中，并且如先前所报道的，βCNC亚基的存在可能与单独的hα CNC 1亚基相比增加这些通道阻断剂的亲和力。该通道的另外两种亚型CNC 2和CNC 3的mRNA也在A549细胞系中表达。本研究记录了可用于体外或体内实验的外用通道阻滞剂的IC 50，以记录气道细胞通过环核苷酸门控阳离子通道的钠吸收。
Using the whole-cell patch-clamp technique, the selectivity and pharmacology of 8-Br-cGMP-stimulated currents in the human alveolar cell line A549 was compared to 8-Br-cGMP-stimulated currents in HK293 cells transfected with hαCNC1. Whole cell currents stimulated by 8-Br-cGMP in HK293 cells transfected with hαCNC1 or A549 cells are carried by inward sodium and outward potassium with nearly the same selectivity. The whole-cell inward currents that are stimulated by 8-Br-cGMP in HK293 cells transfected with hαCNC1 are inhibited by l-cis-diltiazem with an IC50of 154 μm, by 2′,4′-dichlorobenzamil with an IC50of 50 μmand by amiloride with an IC50of 133 μm. The whole-cell inward currents in A549 cells that are stimulated by 8-Br-cGMP, are inhibited by l-cis-diltiazem with an IC50of 87 μm, by 2′4′-dichlorobenzamil with an IC50of 38 μmand by amiloride with an IC50of 32 μmsuggesting that these airway cells contain cyclic nucleotide-gated cation channels. RT-PCR data suggest that mRNA of both αCNC1 and βCNC subunits are present in A549 cells and the presence of the βCNC subunit, may as previously reported, increase the affinity of these channel blockers compared to the hαCNC1 subunit alone. The mRNA of two other isoforms of this channel, CNC2 and CNC3, are also expressed in the A549 cell line. This study documents the IC50of externally applied channel blockers that can be used for in vitro or in vivo experiments to document sodium absorption via cyclic nucleotide-gated cation channels in airway cells.