Identification of Calcium‐Activated Potassium Channels in Cultured Equine Sweat Gland Epithelial Cells
Identification of Calcium‐Activated Potassium Channels in Cultured Equine Sweat Gland Epithelial Cells
复制标题
培养的马汗腺上皮细胞中钙激活钾通道的鉴定
作者：
Yu Huang;W. Ko;Y. Chung;P. Wong
膜片钳记录技术用于检查培养的马汗腺上皮细胞中 K+ 通道的特性。使用对称 K+ 溶液 (140 mM)，鉴定出单个 K+ 通道群，其斜率电导为 187 pS，反转电位约为 0 mV。该通道对 K+ 的选择性高于对 Na+ 的选择性。膜去极化增加了通道活性。 [Ca2+]i 增加 10 倍会导致开路状态概率 (Popen)-电压曲线产生大约 60 mV 的负移。外部施加的四乙铵离子 (TEA+) 导致通道快速且闪烁的阻塞，并降低了单一电流幅度。 TEA+ 以 1:1 的化学计量与阻断位点结合，+40 mV 时解离常数 (Kd) 为 186 ± 27 μM。观察到 Kd 具有弱电压依赖性。伊比利亚毒素 (100 nM) 会降低 Popen，但对单通道电导没有影响。格列本脲 (10 μM) 和细胞内 5'-三磷酸腺苷 (ATP, 1 mM) 均不会改变通道活性。此外，当 ATP 在细胞外应用时，会通过增加 Popen 瞬时激活通道。完整上皮细胞中静息膜电位周围的通道活性较低，表明这些通道可能对静息 K+ 电导没有贡献。然而，该通道可以以受监管的方式激活。 K+通道可能在汗腺跨上皮液分泌中发挥作用。
The patch‐clamp recording technique was used to examine the properties of the K+ channels in cultured equine sweat gland epithelial cells. With symmetric K+ solutions (140 mM), a single population of K+ channels was identified with a slope conductance of 187 pS and a reversal potential of around 0 mV. The channel was selective for K+ over Na+. Channel activity was increased by membrane depolarization. A 10‐fold increase in [Ca2+]i produced an approximate 60 mV negative shift in the open state probability (Popen)‐voltage curve. Externally applied tetraethylammonium ions (TEA+) caused a rapid and flickery block of the channel and reduced the unitary current amplitude. TEA+ bound to the blocking site with stoichiometry of 1:1 and with a dissociation constant (Kd) of 186 ± 27 μM at +40 mV. A weak voltage dependence of Kd was observed. Iberiotoxin (100 nM) reduced Popen but had no effect on single‐channel conductance. Neither glibenclamide (10 μM) nor intracellular adenosine 5′‐triphosphate (ATP, 1 mM) altered channel activity. In addition, ATP, when applied extracellularly, transiently activated the channel by increasing Popen. Channel activity was low around the resting membrane potential in the intact epithelia, indicating that these channels might not contribute to the resting K+ conductance. However, the channel could be activated in a regulated manner. The K+ channels may play a role in transepithelial fluid secretion in sweat gland.
激肽对猪肾乳头集合管细胞原代培养物中生电离子转运的影响。
DOI：
10.1152/ajprenal.1985.249.3.f439
发表时间：
1985
期刊：
The American journal of physiology
影响因子：
--
作者：
Cuthbert,AW;George,AM;MacVinish,L
通讯作者：
MacVinish,L