Extracellular ATP increases [Ca(2+)](i) in distal tubule cells. II. Activation of a Ca(2+)-dependent Cl(-) conductance.
We characterized Cl(-) conductance activated by extracellular ATP in an immortalized cell line derived from rabbit distal bright convoluted tubule (DC1). (125)I(-) efflux experiments showed that ATP increased (125)I(-) loss with an EC(50) = 3 microM. Diphenylamine-2-carboxylate (10(-3) M) and NPPB (10(-4) M) abolished the (125)I(-) efflux. Preincubation with 10 microM 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester or 10(-7) M thapsigargin inhibited the effect of ATP. Ionomycin (2 microM) increased (125)I(-) efflux with a time course similar to that of extracellular ATP, suggesting that the response is dependent on the intracellular Ca(2+) concentration ([Ca(2+)](i)). The ATP agonist potency order was ATP >/= UTP > ATPgammaS. Suramin (500 microM) inhibited the ATP-induced (125)I(-) efflux, consistent with P2 purinoceptors. (125)I(-) effluxes from cells grown on permeable filters suggest that ATP induced an apical efflux that was mediated via apical P2 receptors. Whole cell experiments showed that ATP (100 microM) activated outwardly rectifying Cl(-) currents in the presence of 8-cyclopentyl-1,3-dipropylxanthine, excluding the involvement of P1 receptors. Ionomycin activated Cl(-) currents similar to those developed with ATP. These results demonstrate the presence of a purinergic regulatory mechanism involving ATP, apical P2Y2 receptors, and Ca(2+) mobilization for apical Cl(-) conductance in a distal tubule cell line.
Rubera
I
I
Unité Mixte de Recherche 6548, Centre National de la Recherche Scientifique, Université de Nice-Sophia Antipolis, 06108 Nice Cedex 2, France.
Tauc
M
M
Bidet
M
M
Verheecke-Mauze
C
C
De Renzis
G
G
Poujeol
C
C
Cuiller
B
B
Poujeol
P
P
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D016764:Cell Polarity; D002614:Chelating Agents / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D007457:Iodine Radioisotopes / Q000378:metabolism; D015759:Ionomycin / Q000494:pharmacology; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D009578:Nitrobenzenes / Q000494:pharmacology; D011817:Rabbits; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D058473:Receptors, Purinergic P2Y2; D013498:Suramin / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D002121:Calcium Channel Blockers; D002614:Chelating Agents; D018118:Chloride Channels; D002712:Chlorides; D007457:Iodine Radioisotopes; D009578:Nitrobenzenes; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D014970:Xanthines; C047633:5-(4-nitrophenyl)-2,4-pentadienal; D015759:Ionomycin; D013498:Suramin; D000255:Adenosine Triphosphate; C051360:1,3-dipropyl-8-cyclopentylxanthine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium; D014544:Uridine Triphosphate