Fig. 3.

CCh-induced SPCU depends on both voltage-gated Ca²⁺ entry and Ca²⁺ release from intracellular stores: effect of block of voltage-gated Ca²⁺ channels with 5 μM nicardipine (A) and depletion of intracellular Ca²⁺ stores with 10 μM CPA (B). The imaging was performed at 26 Hz (A) and 23 Hz (B). The plot shows the time course of the normalized fluo-4 fluorescence intensity averaged within sub-PM regions (outlined) in control (a), after incubation with 5 μM nicardipine or 10 μM CPA (b) and after incubation with 5 μM nicardipine in the presence of 10 μM CPA (c). A 10-min period was allowed between subsequent 600-ms pulses of 10 μM CCh. The galleries below the plots show sequential confocal images (after rotation by 90°) captured during the highlighted periods.