The voltage clamp protocol is shown in the inset. Current traces in the absence (A) and presence of 10 μm Gd3+ (B) are shown. C, control current-voltage relationships of the instantaneous current, Ibkg (□), and time-dependent current, ICl,ir (▴), in the absence of Gd3+. D, current-voltage relationships of the currents in the presence of 10 μm Gd3+. This experiment is typical of 5 cells.