Downregulation of volume-activated Cl- currents during muscle differentiation.
We have used the whole cell configuration of the patch-clamp technique to investigate volume-activated Cl- currents in BC3H1 and C2C12 cells, two mouse muscle cell lines that can be switched from a proliferating to a differentiated musclelike state. Reducing the extracellular osmolality by 40% evoked large Cl- currents in proliferating BC3H1 and C2C12 cells. These currents were outwardly rectifying and had an anion permeability sequence as follows: I- > Br- > Cl- >> gluconate. They were inhibited by >50% by flufenamic acid (500 microM), niflumic acid (500 microM), and 5-nitro-2-(3-phenylpropylamino)benzoic acid (100 microM) but were relatively insensitive to tamoxifen (100 microM). A reduction in the serum concentration in the culture medium induced growth arrest in both cell lines, and the cells started to differentiate into spindle-shaped nonfusing muscle cells (BC3H1) or myotubes (C2C12). This differentiation was accompanied by a drastic decrease in the magnitude of the volume-activated Cl- currents. The close correlation between volume-activated Cl- currents and cell proliferation suggests that these currents may be involved in cell proliferation.
Voets
T
T
Laboratorium voor Fysiologie, Katholieke Universiteit Leuven, Belgium.
Wei
L
L
De Smet
P
P
Van Driessche
W
W
Eggermont
J
J
Droogmans
G
G
Nilius
B
B
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002712:Chlorides / Q000037:antagonists & inhibitors / Q000502:physiology*; D004553:Electric Conductivity; D005439:Flufenamic Acid / Q000494:pharmacology; D051379:Mice; D009132:Muscles / Q000166:cytology* / Q000502:physiology*; D009544:Niflumic Acid / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology
D002712:Chlorides; D009579:Nitrobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D009544:Niflumic Acid; D005439:Flufenamic Acid