Fig. 1.
Dependence of capacitance response on size of calcium current. The average capacitance jump is plotted versus calcium current amplitude. Pulses were 250 msec depolarizations from the holding potential of −60 to −20, −10, or 0 mV. Each data point is the average of 4–11 responses, and thevertical lines show ± 1 SEM. Across-cell averages at each current range were obtained by binning in 50 pA increments of observed calcium current. The position of each data point along the abscissa shows the average current within each bin. The standard pipette solution (see Materials and Methods) was used, with either 0.5 mm BAPTA (filled circles) or 0.5 mm EGTA (open circles). Results are shown from 13 cells for EGTA and 29 cells for BAPTA.