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  • Title: ATP-inhibitable Cl- channel in apical membranes of cultured rabbit cortical collecting duct cells.
    Author: Superdock KR, Snyders DK, Breyer MD.
    Journal: Am J Physiol; 1993 Oct; 265(4 Pt 1):C957-65. PubMed ID: 8238321.
    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.
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