A volume-sensitive chloride conductance in human colonic cell line T84.
A volume-sensitive chloride conductance in human colonic cell line T84.
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人结肠细胞系 T84 中的体积敏感氯离子电导。
DOI：
10.1152/ajpcell.1989.256.6.c1111
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Frizzell,RA
中科院分区：
文献类型：
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作者：
Worrell,RT;Butt,AG;Cliff,WH;Frizzell,RA
用全细胞膜片钳技术，以Cl为膜离子，对结肠癌细胞株T84进行了研究。跨膜电流最初很小（+100 mV时约为50 pA），但在5-10 min内稳定增加至1-3 nA的平均值。该电流的发展与可见的细胞肿胀相关，没有形状变化或膜起泡。通过向浴中加入50-75 mM蔗糖或当移液管渗透压摩尔浓度降低等量时，恢复基础预溶胀电流水平。这些结果表明，等渗移液器填充液的行为就像是高渗的，大约60 mosmol/kgH 2 O。穿过肿胀诱导电导的电流被向外整流，并在超极化电压下显示激活，在去极化电压下显示失活。它们是Cl选择性的，因为当浴[Cl]变化时，电流的反向电势接近Cl平衡电势。在非溶胀条件下（浴溶液，300 mosmol/kgH 2 O;移液器溶液，240 mosmol/kgH 2 O），可分辨单通道阶跃（+100 mV时约9 pA）。的单通道特性是类似的宏观电流记录肿胀的细胞，显示在正电压和向外整流的电流-电压关系的失活。这些单通道事件的总和产生的电流是从肿胀的细胞，这意味着多个通道与这些属性的激活是肿胀诱导的Cl电导的基础相似。当T84细胞膨胀时，这种体积敏感的Cl电导将有助于调节体积减小。它的关系，在这些细胞中的分泌氯电导是未知的。
The chloride-secreting colonic cell line, T84, was studied under whole cell patch clamp with Cl as the permeant ion in pipette and bath solutions. Transmembrane current was initially small (approximately 50 pA at +100 mV) but increased steadily to average values of 1-3 nA within 5-10 min. The development of this current was associated with visible cell swelling, either without a shape change or with membrane blebbing. Basal, preswelling current levels were restored by the addition of 50-75 mM sucrose to the bath or when pipette osmolality was reduced by an equivalent amount. These findings suggest that an isosmotic pipette filling solution behaves as if it is hypertonic by approximately 60 mosmol/kgH2O to the bath. Currents traversing the swelling-induced conductance were outwardly rectified and showed activation at hyperpolarizing voltages and inactivation at depolarizing voltages. They were Cl selective because the reversal potential for current flow approached the Cl equilibrium potential when bath [Cl] was varied. Under nonswelling conditions (bath solution, 300 mosmol/kgH2O; pipette solution, 240 mosmol/kgH2O), single-channel steps (approximately 9 pA at +100 mV) could be resolved. The single-channel characteristics were similar to the macroscopic currents recorded from swollen cells, showing inactivation at positive voltages and an outwardly rectified current-voltage relation. Summation of these single-channel events yielded currents that were similar to those from swollen cells, implying that activation of multiple channels with these properties is the basis of the swelling-induced Cl conductance. This volume-sensitive Cl conductance would contribute to a regulatory volume decrease when T84 cells swell. Its relation to the secretory Cl conductance in these cells is unknown.