上皮细胞系T84中由环磷酸腺苷（cAMP）激活的低电导氯离子通道。

Low-conductance chloride channel activated by cAMP in the epithelial cell line T84.

作者信息

Tabcharani J A, Low W, Elie D, Hanrahan J W

机构信息

Department of Physiology, McGill University, Montréal, Québec, Canada.

出版信息

FEBS Lett. 1990 Sep 17;270(1-2):157-64. doi: 10.1016/0014-5793(90)81257-o.

DOI:10.1016/0014-5793(90)81257-o

PMID:1699790

Abstract

We have studied the modulation and pharmacological properties of two anion channels in T84 cells by recording single channel and transepithelial currents. One channel had an outwardly rectifying current-voltage I/V curve, was rarely active in cell-attached patches, and was unaffected by cAMP. The other channel had lower conductance (8.7 pS at 37 degrees C) and a more ohmic I/V relationship. Exposure to cAMP increased the probability of observing low-conductance channel activity in cell-attached patches greater than 6-fold. Extracellular DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid) or [IAA-94 (an indanyloxyacetic acid) inhibited the outward rectifier but did not affect the low-conductance channel or cAMP-stimulated transepithelial current. These results suggest the low-conductance Cl channel may contribute to apical membrane conductance during cAMP-stimulated secretion.

摘要

我们通过记录单通道电流和跨上皮电流，研究了T84细胞中两种阴离子通道的调节作用和药理学特性。一种通道具有外向整流的电流-电压（I/V）曲线，在细胞贴附式膜片中很少有活性，且不受环磷酸腺苷（cAMP）的影响。另一种通道具有较低的电导（37℃时为8.7皮安）和更接近欧姆定律的I/V关系。暴露于cAMP会使在细胞贴附式膜片中观察到低电导通道活性的概率增加6倍以上。细胞外应用4,4'-二异硫氰基芪-2,2'-二磺酸（DIDS）或吲哚氧基乙酸（IAA-94）可抑制外向整流通道，但不影响低电导通道或cAMP刺激的跨上皮电流。这些结果表明，低电导氯离子通道可能在cAMP刺激的分泌过程中对顶端膜电导有贡献。