Similar chloride channels in the connecting tubule and cortical collecting duct of the mouse kidney.
Using the patch-clamp technique, we investigated Cl- channels on the basolateral membrane of the connecting tubule (CNT) and cortical collecting duct (CCD). We found a approximately 10-pS channel in CNT cell-attached patches. Substitution of sodium gluconate for NaCl in the pipette shifted the reversal potential by +25 mV, whereas N-methyl-D-gluconate chloride had no effect, indicating anion selectivity. On inside-out patches, we determined a selectivity sequence of Cl- > Br- approximately NO3(-) > F-, which is compatible with that of ClC-K2, a Cl- channel in the distal nephron. In addition, the number of open channels (NP(o)) measured in cell-attached patches was significantly increased when Ca2+ concentration or pH in the pipette was increased, which is another characteristic of ClC-K. These findings suggest that the basis for this channel is ClC-K2. A similar Cl- channel was found in CCD patches. Because CNT and CCD are heterogeneous tissues, we studied the cellular distribution of the Cl- channel using recording conditions (KCl-rich solution in the pipette) that allowed us to detect simultaneously Cl- channels and inwardly rectifying K+ channels. We detected Cl- channels alone in 45% and 42% and K+ channels alone in 51% and 58% of CNT and CCD patches, respectively. Cl- and K+ channels were recorded simultaneously from two patches (4% of patches) in the CNT and from none of the patches in the CCD. This indicates that Cl- and K+ channels are located in different cell types, which we suggest may be the intercalated cells and principal cells, respectively.
Nissant
Antoine
A
Université Pierre et Marie Curie & CNRS, Laboratoire de Physiologie et Génomique des Cellules Rénales, UMR 7134, Institut des Cordeliers, 15 rue de l'Ecole de Médecine, 75270 Paris Cedex 06, France.
Paulais
Marc
M
Lachheb
Sahran
S
Lourdel
Stéphane
S
Teulon
Jacques
J
D000818:Animals; D002118:Calcium / Q000032:analysis; D018118:Chloride Channels / Q000032:analysis* / Q000502:physiology; D004553:Electric Conductivity; D005942:Gluconates; D006863:Hydrogen-Ion Concentration; D007395:Interneurons / Q000737:chemistry; D007684:Kidney Tubules / Q000737:chemistry*; D007685:Kidney Tubules, Collecting / Q000737:chemistry*; D008297:Male; D051379:Mice; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000032:analysis; D012965:Sodium Chloride
D018118:Chloride Channels; D005942:Gluconates; D015221:Potassium Channels; D012965:Sodium Chloride; C030691:gluconic acid; D002118:Calcium