ISSN:
1432-1424
Keywords:
Key words: Trachea — K+ channels — Basolateral membrane — cAMP
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002329900149
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