A voltage-dependent K+ current has been revealed in whole-cell recordings carried out on immortalized cells obtained from the human tracheal epithelium. At positive membrane potentials the current shows a time dependent inactivation which is accelerated by increasing the depolarizing step. Forskolin, a direct activator of adenylyl cyclase, and verapamil, a Ca2+ channel blocker, induce the K+ current to inactivate more rapidly. Control experiments show that the action of these two compounds is not mediated by cyclic AMP and Ca2+. The application of 1,9-dideoxyforskolin, an analogue which does not stimulate adenylate cyclase, inhibits the current in the same way as forskolin; on the contrary, the dibutyryl analogue of cyclic AMP is ineffective. Furthermore, eliminating extracellular Ca2+ does not affect K+ current kinetics. Tetraethylammonium is an effective blocker of this current with an IC50 of 0.3 mM.

Galietta, L.J.V., Rasola, A., Barone, V., Gruenert, D.C., & Romeo, G. (1991). A forskolin and verapamil sensitive potassium current in human tracheal cells. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 179(3), 1155-1160 [10.1016/0006-291X(91)91692-6].

A forskolin and verapamil sensitive potassium current in human tracheal cells

BARONE, V.;
1991

Abstract

A voltage-dependent K+ current has been revealed in whole-cell recordings carried out on immortalized cells obtained from the human tracheal epithelium. At positive membrane potentials the current shows a time dependent inactivation which is accelerated by increasing the depolarizing step. Forskolin, a direct activator of adenylyl cyclase, and verapamil, a Ca2+ channel blocker, induce the K+ current to inactivate more rapidly. Control experiments show that the action of these two compounds is not mediated by cyclic AMP and Ca2+. The application of 1,9-dideoxyforskolin, an analogue which does not stimulate adenylate cyclase, inhibits the current in the same way as forskolin; on the contrary, the dibutyryl analogue of cyclic AMP is ineffective. Furthermore, eliminating extracellular Ca2+ does not affect K+ current kinetics. Tetraethylammonium is an effective blocker of this current with an IC50 of 0.3 mM.
Galietta, L.J.V., Rasola, A., Barone, V., Gruenert, D.C., & Romeo, G. (1991). A forskolin and verapamil sensitive potassium current in human tracheal cells. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 179(3), 1155-1160 [10.1016/0006-291X(91)91692-6].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11365/38422
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