Tolbutamide-sensitive potassium conductance in the basolateral membrane of A6 cells

Details

Serval ID
serval:BIB_E8B019B71E92
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Tolbutamide-sensitive potassium conductance in the basolateral membrane of A6 cells
Journal
Journal of Membrane Biology
Author(s)
Broillet  M. C., Horisberger  J. D.
ISSN
0022-2631 (Print)
Publication state
Published
Issued date
06/1993
Volume
134
Number
3
Pages
181-8
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Jun
Abstract
K+ channels sensitive to intracellular ATP (KATP channels) have been described in a number of cell types and are selectively inhibited by sulfonylurea drugs. To look for the presence of this type of K+ channel in the basolateral membrane of tight epithelia, we have used an amphibian renal cell line, the A6 cells, grown on filters. After the selective permeabilization of the apical membrane with amphotericin B, the basolateral conductance was studied under voltage-clamp conditions. Tolbutamide inhibited 65.8 +/- 6.3% of the barium-sensitive current. The tolbutamide-sensitive conductance had an equilibrium potential of -83 +/- 1 mV and was inward rectifying in spite of the outwardly directed K+ gradient. Similar results were obtained with glibenclamide. The half-inhibition constants were 25.7 +/- 3.0 microM and 0.114 +/- 0.018 microM for tolbutamide and glibenclamide, respectively. To study the relation between cellular ATP and the activity of this conductance, A6 cells were treated with glucose (5 mM) and insulin (250 microU/ml). This maneuver significantly increased the cellular ATP and abolished the tolbutamide-sensitive conductance. A sulfonylurea-sensitive K+ conductance is present and active in the basolateral membrane of A6 cells. This conductance appears to be modulated by physiological changes of intracellular ATP.
Keywords
Adenosine Triphosphate/metabolism Amphibia Animals Cell Line Cell Membrane/metabolism/ultrastructure Epithelium/metabolism Glucose/pharmacology Glyburide/pharmacology Insulin/pharmacology Kidney/chemistry/*drug effects/metabolism Membrane Potentials/drug effects Potassium Channels/*drug effects/physiology Sulfonylurea Compounds/pharmacology Tolbutamide/*pharmacology
Pubmed
Web of science
Create date
24/01/2008 12:38
Last modification date
20/08/2019 16:11
Usage data