Figure 10.
Effect of cell volume on the rate of inactivation of KCC at 25°C. Cells were preincubated in hyposmotic (200 mosmol/kg) medium for 15 min at 37°C to activate KCC and were pelleted and maintained at 37°C before resuspending at 25°C in 86Rb-containing media of the indicated osmolality. All flux mediate contained 5 mM KCl and 10−4 M ouabain. The solid curves through the data represent single exponential decreases in the flux (), with initial flux equal to the initial slope of the curve in 196 mosmol/kg medium. The lag times for the individual curves (from the top) are 17.5, 11.3, 6.0, 3.7, and 1.8 min.