title: ATP-inhibitable Cl- channel in apical membranes of cultured rabbit cortical collecting duct cells.
abstract: Excised patches of apical membranes from immunodissected rabbit cortical collecting duct cells in primary culture were studied by the patch-clamp technique. Barium (1 mM) and tetraethylammonium chloride (5 mM) were added to all solutions to block potassium channel activity. A unique channel was observed that exhibited inward rectification under symmetrical ionic conditions with a measured chord conductance of 54.0 +/- 2.5 pS at -80 mV (n = 11) and 22.1 +/- 1.7 pS at +80 mV (n = 5). This channel was chloride selective, with a PNa:PCl of 0.16 (n = 3). Kinetic analysis revealed a voltage-independent open-time probability of 0.80 +/- 0.07 (n = 6). Open-time probability within bursts was 0.96 +/- 0.01. Addition of ATP to the cytosolic surface of the channel resulted in a dose-dependent decrease in open probability, with a threshold effect at 10(-4) M, due to a reduction in burst open time. The effect of ATP was immediate, rapidly reversible at room temperature, and mimicked by GTP, adenosine 5'-O-(3-thiotriphosphate), and guanosine 5'-O-(3-thiotriphosphate). This channel may link epithelial chloride permeability to cellular ATP content in the rabbit cortical collecting duct.
authors.affiliation: Department of Medicine, Vanderbilt University, Nashville, Tennessee 37212.
authors.forename: K R
authors.initials: KR
authors.lastname: Superdock
authors.forename: D K
authors.initials: DK
authors.lastname: Snyders
authors.forename: M D
authors.initials: MD
authors.lastname: Breyer
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D018118:Chloride Channels / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000502:physiology; D004594:Electrophysiology; D007477:Ions; D007672:Kidney Cortex; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D011817:Rabbits
chemical_list: D018118:Chloride Channels; D007477:Ions; D000255:Adenosine Triphosphate