Outward K+ current in epithelial cells isolated from intermediate portion of endolymphatic sac of guinea pigs.
Outward K+ current in epithelial cells isolated from intermediate portion of endolymphatic sac of guinea pigs.
复制标题
从豚鼠内淋巴囊中间部分分离的上皮细胞中的外向 K 电流。
DOI：
10.1152/ajpcell.1996.271.5.c1765
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
N. Mori
中科院分区：
文献类型：
--
作者：
D. Wu;N. Mori
应用全细胞膜片钳技术研究了豚鼠内淋巴囊（ES）中段上皮细胞的离子电流。从-60 mV的保持电位开始的去极化电压阶跃诱导了时间和电压依赖性外向电流，这与延迟整流K+电流相当。在电流钳模式下的平均静息膜电位为-54.8 +/-11 mV（n = 45），这与从电压钳模式下外向电流的电流-电压（I-V）关系获得的零电流电位值（-55.6 +/-0.8 mV，n = 32）相似。在标准外部溶液中，尾电流的I-V关系显示反转电位（Erev）为-78.1 +/- 0.9 mV（n = 19）。外向电流的Erev与细胞外K+浓度的对数呈线性关系。细胞外K+浓度每变化10倍，斜率为48 mV。K+电流激活、失活和K+尾电流失活的时间常数均具有电压依赖性。钾电流的稳态激活和失活与电压呈S形关系。50%最大激活电压和斜率因子分别为-21和11 mV（n = 8）。50%最大失活电压和斜率因子分别为-45和13 mV（n = 7）。通过外部施加的ImM 4-氨基吡啶（4-AP）、5 mM Ba 2+和20 mM四乙基氯化铵（TEA）阻断K+电流。电流对4-AP和Ba ~（2+）的敏感性高于对TEA的敏感性。消除外部Ca ~（2+）和增加内部Ca ~（2+）均不能显著改变电流，表明K ~+电流可能不依赖于Ca ~（2+）。结果表明，在ES的中间部分的上皮细胞具有延迟整流K+电流，这可能涉及膜的稳定性或在细胞质和细胞外环境之间的离子平衡。
Ion currents in epithelial cells isolated from the intermediate portion of endolymphatic sac (ES) in guinea pigs were investigated with the use of the whole cell patch-clamp technique. Depolarizing voltage steps from a holding potential of -60 mV induced a time- and voltage-dependent outward current, which is comparable to that of delayed rectifying K+ currents. The average resting membrane potential in the current-clamp mode was -54.8 +/- 11 mV (n = 45), which was similar to the value of zero current potential (-55.6 +/- 0.8 mV, n = 32) obtained from current-voltage (I-V) relationships of outward currents in voltage-clamp mode. The I-V relationship of the tail current exhibited a reversal potential (Erev) of -78.1 +/- 0.9 mV (n = 19) in standard external solution. The Erev of the outward current was linearly related to the logarithm of extracellular K+ concentrations. The slope was 48 mV per 10-fold change in extracellular K+ concentrations. The time constants of K+ current activation, inactivation, and K+ tail current deactivation were voltage dependent. The steady-state activation and inactivation of K+ current exhibited a sigmoidal relationship to voltage. The 50% maximal activation voltage and slope factor were -21 and 11 mV (n = 8), respectively. The 50% maximal inactivation voltage and slope factor were -45 and 13 mV (n = 7), respectively. The K+ current was blocked by externally applied 1 mM 4-aminopyridine (4-AP), 5 mM Ba2+ and 20 mM tetraethylammonium chloride (TEA). The sensitivity of the current to 4-AP and Ba2+ was higher than that to TEA. Elimination of external Ca2+ and increase of internal Ca2+ failed to significantly change the current, suggesting that the K+ current may be Ca2+ independent. The results show that epithelial cells in the intermediate portion of the ES possess a delayed-rectifier K+ current, which may be involved in membrane stability or in the ion balance between the cytosol and the extracellular environment.
来自分离的青蛙晶状体上皮细胞的钾电流。
影响因子：
3.4
作者：
Cooper,K;Watsky,M;Rae,J
通讯作者：
Rae,J
影响因子：
2.5
作者：
RENNIE, KJ;CORREIA, MJ
通讯作者：
CORREIA, MJ