Taurine permeation through swelling-activated anion conductance in rat IMCD cells in primary culture.
Whole cell recordings were performed on rat inner medullary collecting duct (IMCD) cells in primary culture. With 140 mmol/l CsCl in bath and pipette we find within 10 min a 60-fold increase in membrane conductance from 0.02 +/- 0.003 to 1.2 +/- 0.1 nS/pF when bath osmolarity is decreased from 600 to 500 mosmol/l. The effect is due to the activation of an outwardly rectifying anion conductance with the anion selectivity SCN- > I- > NO-3 > Br- > Cl- > F- > isethionate > gluconate > or = aspartate > or = glutamate. A relative permeability of the organic osmolyte taurine to Cl- (Ptaurine: PCl-) of 0.15 was detected. With taurine in pipette and bath, the channel exhibits a nearly identical activation and sensitivity profile to a variety of anion channel blockers as under symmetrical Cl- conditions. Furthermore, the 50% inhibitory concentration value for the effect of 5-nitro-2-(3-phenylpropylamino)benzoate on both currents is virtually identical. We conclude that hypotonic stress increases the anion conductance of rat IMCD cells and that this anion conductance mediates taurine efflux.
Boese
S H
SH
Max-Planck-Institut für Molekulare Physiologie, Abteilung Epithelphysiologie, Dortmund, Germany.
Wehner
F
F
Kinne
R K
RK
D000818:Animals; D000838:Anions / Q000378:metabolism*; D002478:Cells, Cultured; D002712:Chlorides / Q000502:physiology; D004553:Electric Conductivity; D007679:Kidney Medulla; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism* / Q000502:physiology*; D008297:Male; D009995:Osmosis; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000493:pharmacokinetics* / Q000502:physiology
D000838:Anions; D002712:Chlorides; D013654:Taurine