Abstract.
To study K+ channels in the basolateral membrane of chloride-secreting epithelia, rat tracheal epithelial monolayers were cultured on permeable filters and mounted into an Ussing chamber system. The mucosal membrane was permeabilized with nystatin (180 μg/ml) in the symmetrical high K+ (145 mm) Ringer solution. During measurement of the macroscopic K+ conductance properties of the basolateral membrane under a transepithelial voltage clamp, we detected at least two types of K+ currents: one is an inwardly rectifying K+ current and the other is a slowly activating outwardly rectifying K+ current. The inwardly rectifying K+ current is inhibited by Ba2+. The slowly activating K+ current was potentiated by cAMP and inhibited by clofilium, phorbol 12-myristae 13-acetate (PMA) and lowering temperature. This is consistent with the biophysical characteristics of I SK channel. RT-PCR analysis revealed the presence of I SK cDNA in the rat trachea epithelia. Although 0.1 mm Ba2+ only had minimal affect on short-circuit current (I sc) induced by cAMP in intact epithelia, 0.1 mm clofilium strongly inhibited it. These results indicate that I SK might be important for maintaining cAMP-induced chloride secretion in the rat trachea epithelia.
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Received: 1 March 1996/Revised: 5 August 1996
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Hwang, TH., Suh, DJ., Bae, HR. et al. Characterization of K+ Channels in the Basolateral Membrane of Rat Tracheal Epithelia . J. Membrane Biol. 154 , 251 –257 (1996). https://doi.org/10.1007/s002329900149
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DOI: https://doi.org/10.1007/s002329900149