Fig. 10. Effect of SV2A and SV2C depletion on membrane capacitance changes. INS-1E cells were transiently co-transfected with GFP and an empty vector (Control), or with either the SV2A siRNA-3 (siRNA SV2A) or the SV2C siRNA-2 (siRNA SV2C). Four days later, recordings were performed on GFP-expressing cells. (A) Single cell capacitance traces evoked by ten depolarizing pulses to 0 mV from a holding potential of -70 mV (left panels), and the corresponding Ca²⁺-current traces of the first depolarization in the pulse train (right panels). The pulse train was started 60 seconds after establishing the whole-cell configuration (bottom). C_m, membrane capacitance; fF, femtoFarad. (B) Capacitance changes normalized to the Ca²⁺ current of the first pulse for every cell, after one and ten pulses. Values are the mean±s.e. of 8 to 12 cells. ^*P<0.05 vs. levels in the control. pA, picoAmpere; pF, picoFarad. (C) Ca²⁺-current density measured from the first depolarization in the pulse train. The Ca²⁺ current was evaluated 3 milliseconds after the onset of depolarization to avoid contamination of fast Na⁺ current.