Conductive properties of a rabbit cortical collecting duct cell line: regulation by isoproterenol.
The present study was carried out to characterize the membrane conductive properties of RCCT-28A cells, a continuous cell line derived from rabbit cortical collecting duct (CCD). RCCT-28A cells have many phenotypic properties of acid-secreting intercalated cells (A-IC). Using the whole cell patch-clamp technique, we found that the cells are conductive to Cl-, but not to Na+ or K+. The beta-adrenergic agonists isoproterenol (2 x 10(-6) M) and adenosine 3',5'-cyclic monophosphate (cAMP, 10(-4) M) increased the whole cell Cl- conductance. Protein kinase A (150 nM) in the patch pipette (i.e., intracellular solution) also increased whole cell Cl- conductance. Because isoproterenol increases cAMP levels in these cells, we conclude that isoproterenol stimulates the Cl- conductance by increasing cell cAMP, which in turn activates protein kinase A. In contrast, vasopressin does not increase cAMP in these cells and did not increase the Cl- conductance. In conclusion, these experiments show that RCCT-28A cells, like A-IC, are conductive only to Cl-. Thus RCCT-28A cells are a good model with which to study Cl- channels in the collecting duct.
Dietl
P
P
Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire 03756.
Kizer
N
N
Stanton
B A
BA
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane; D002712:Chlorides / Q000502:physiology; D004553:Electric Conductivity; D007545:Isoproterenol / Q000494:pharmacology*; D007672:Kidney Cortex; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000502:physiology*; D011817:Rabbits
D002712:Chlorides; D007545:Isoproterenol