Swelling-induced and depolarization-induced C1-channels in normal and cystic fibrosis epithelial cells.
Swelling-induced and depolarization-induced C1-channels in normal and cystic fibrosis epithelial cells.
复制标题
正常和囊性纤维化上皮细胞中肿胀诱导和去极化诱导的 C1 通道。
DOI：
10.1152/ajpcell.1991.261.4.c658
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Wine,JJ
中科院分区：
文献类型：
--
作者：
Solc,CK;Wine,JJ
细胞肿胀诱导的Cl-电流的特点是在整个细胞和单通道水平在原代培养的正常和囊性纤维化（CF）上皮细胞和T84细胞系。在正常和CF细胞中记录的电流是无法区分的。在22- 2 - 4摄氏度下，移液管中加入等渗CsCl，未肿胀细胞在100 mV时的初始全细胞外向电流密度为2-4 pA/pF。在全细胞记录期间，电流密度随着时间的推移而增加，在等渗溶液中高达100 pA/pF，在低渗浴中高达200 pA/pF，但值通常在10至70 pA/pF之间。电流是向外整流的，在负电压下活性，在约40 mV以上开始升高，并被4，4 '-二硝基芪-2，2'-二磺酸（DNDS）阻断。单个Cl-通道（约50 pS，接近0 mV）与外向整流电流-电压关系记录在细胞附着和外向补丁肿胀细胞。通道在负电压下大部分开放，在正电压下失活，具有与全细胞电流类似的电压依赖性。通道活性在密封形成后迅速下降（通道下降）。肿胀诱导的通道活动停止后，向外整流，去极化诱导的氯离子通道（ORDIC通道）被激活，在一些补丁。肿胀诱导的单通道电流和ORDIC单通道电流相似，但观察到一些一致的差异。在静息电压（-70至-50 mV）下，ORDIC通道通常关闭，而肿胀诱导的通道在此电压范围内始终打开。此外，与溶胀诱导的通道相比，在更高的正电压（约90 vs.约50 mV）下，ORDIC通道开始振荡，整流更多，电导更小（接近0 mV时约为25 pS），平均开放持续时间更短（约70 vs.约350 ms），开放通道噪声更大。这两种类型的电流可能来自不同的通道蛋白或来自不同状态的单个通道分子。
Cl- currents induced by cell swelling were characterized at the whole cell and single-channel levels in primary cultures of normal and cystic fibrosis (CF) epithelial cells and in the T84 cell line. Currents recorded in normal and CF cells were indistinguishable. At 22-24 degrees C with isotonic CsCl in the pipette, initial whole cell outward current density at 100 mV in unswollen cells was 2-4 pA/pF. The current density increased with time during whole cell recording up to 100 pA/pF in isotonic solutions and up to 200 pA/pF in a hypotonic bath, though values typically ranged between 10 and 70 pA/pF. Currents were outwardly rectifying, active at negative voltages, started to inactivate above approximately 40 mV, and were blocked by 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS). Single Cl- channels (approximately 50 pS near 0 mV) with an outwardly rectifying current-voltage relation were recorded in cell-attached and outside-out patches from swollen cells. The channels were mostly open at negative voltages and inactivated at positive voltages with a voltage dependence similar to the whole cell currents. Channel activity decreased rapidly (channel rundown) after seal formation. After swelling-induced channel activity had ceased, outwardly rectifying, depolarization-induced Cl- channels (ORDIC channels) were activated in some patches. The swelling-induced and ORDIC single-channel currents were similar, but some consistent differences were observed. ORDIC channels were often closed at resting voltages (-70 to -50 mV), while swelling-induced channels were always open in this voltage range. In addition, ORDIC channels started to inactivate at more positive voltages (approximately 90 vs. approximately 50 mV), rectified more, and had smaller conductances (approximately 25 pS near 0 mV), shorter mean open durations (approximately 70 vs. approximately 350 ms), and more open-channel noise than swelling-induced channels. The two types of currents might arise from separate channel proteins or from a single channel molecule in different states.