The Role of the Basolateral Outwardly Rectifying Chloride Channel in Human Airway Epithelial Anion Secretion
| Autor: | S. F. Paul Man, Artur J. Szkotak, Marek Duszyk |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Anions
Pulmonary and Respiratory Medicine Nystatin Patch-Clamp Techniques Vasodilator Agents Clinical Biochemistry Adenosine-5'-(N-ethylcarboxamide) Respiratory Mucosa 4 4'-Diisothiocyanostilbene-2 2'-Disulfonic Acid Permeability chemistry.chemical_compound Chloride Channels medicine Humans Secretion Patch clamp Molecular Biology Cells Cultured Forskolin Ionophores Chemistry Receptors Purinergic P1 Cell Polarity Cell Biology Apical membrane Adenosine Adenosine receptor Biochemistry Permeability (electromagnetism) Chloride channel Biophysics Signal Transduction medicine.drug |
| Zdroj: | American Journal of Respiratory Cell and Molecular Biology. 29:710-720 |
| ISSN: | 1535-4989 1044-1549 |
| DOI: | 10.1165/rcmb.2003-0109oc |
| Popis: | The purpose of this study was to characterize basolateral anion channels in Calu-3 and normal human bronchial epithelial cells, and their role in anion secretion. Patch clamp studies identified an outwardly rectifying Cl- channel (ORCC), which could be activated by the adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine (NECA). Short-circuit current measurements revealed that NECA activates a basolateral, but not an apical, anion conductance sensitive to 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid, and to 9-anthracenecarboxylic acid, but not to 4,4'-dinitrostilbene-2,2'-disulfonic acid. Apical membrane permeabilization studies confirmed the presence of basolateral anion channels, established their halide permeability sequence (Cl-/= Br-I-), and demonstrated their outwardly rectifying nature. Experiments using H-89, forskolin, and Ht31 demonstrated that adenosine receptor dependent activation of basolateral ORCC was cAMP- and potentially A-kinase anchoring protein-dependent. Neither BAPTA-AM treatment nor basolateral Ca2+ removal had any effect on the activation of these channels. Anion replacement and 36Cl- flux studies show that Calu-3 cells primarily secrete HCO3- when stimulated with NECA, and that Cl- secretion can be stimulated by blocking basolateral ORCC, whereas normal human bronchial epithelial cells exclusively secrete Cl- under all conditions studied. We propose a novel model of anion secretion in which ORCC recycles Cl- across the basolateral membrane, allowing preferential HCO3- secretion. |
| Databáze: | OpenAIRE |
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