培养的人胃细胞（HGT-1）质膜中的一种环磷酸腺苷激活的氯离子通道。

A cAMP-activated chloride channel in the plasma membrane of cultured human gastric cells (HGT-1).

作者信息

Sandle G I, Fraser G, Long S, Warhurst G

机构信息

Manchester Epithelial Membrane Research Centre, University of Manchester, UK.

出版信息

Pflugers Arch. 1990 Nov;417(3):259-63. doi: 10.1007/BF00370990.

DOI:10.1007/BF00370990

PMID:2177182

Abstract

Hydrochloric acid (HCl) secretion by gastric parietal cells involves an apical Cl- conductance, the properties of which have not been defined. In the present study, forskolin and histamine [agonists that increase intracellular cyclic adenosine monophosphate (cAMP)], and dibutyryl cAMP, activated channels in previously quiescent cell-attached membrane patches on cultured human gastric cells (HGT-1). In the cell-attached configuration (Cl- 149 mmol/l in bath and pipette), channels exhibited outward rectification, voltage dependence, inward current (-0.7 pA) at zero holding potential and a reversal potential of +24 mV, consistent with the presence of a Cl- conductive pathway. In excised inside-out patches, channels (i) exhibited degrees of outward rectification and voltage dependence that were comparable to those seen in cell-attached patches, (ii) demonstrated a -21 mV shift of their reversal potential when bath Cl- was decreased from 149 mmol/l to 53 mmol/l (calculated Cl-:cation permeability ratio 17:1), and (iii) were highly sensitive to the Cl- channel blocker diphenylamine-2-carboxylic acid (DPC, 10(-3) mol/l). This cAMP-activated Cl- channel bears many similarities to other Cl- channels within intestinal epithelia, and may represent the apical Cl- channel operating in HCl-secreting gastric parietal cells.

摘要

胃壁细胞分泌盐酸（HCl）涉及顶端Cl⁻电导，但其特性尚未明确。在本研究中， Forskolin和组胺[可增加细胞内环磷酸腺苷（cAMP）的激动剂]以及二丁酰cAMP，激活了培养的人胃细胞（HGT-1）上先前静止的细胞贴附膜片上的通道。在细胞贴附状态下（浴液和微管中Cl⁻为149 mmol/L），通道表现出外向整流、电压依赖性、零钳制电位下的内向电流（-0.7 pA）和+24 mV的反转电位，这与存在Cl⁻传导途径一致。在切除的内向外膜片中，通道（i）表现出的外向整流程度和电压依赖性与细胞贴附膜片中观察到的相当，（ii）当浴液Cl⁻从149 mmol/L降至53 mmol/L时，其反转电位发生了-21 mV的偏移（计算得出的Cl⁻:阳离子渗透率比为17:1），并且（iii）对Cl⁻通道阻滞剂二苯胺-2-羧酸（DPC，10⁻³ mol/L）高度敏感。这种cAMP激活的Cl⁻通道与肠上皮内的其他Cl⁻通道有许多相似之处，可能代表在分泌HCl的胃壁细胞中起作用的顶端Cl⁻通道。