Figure 2. The GTP-γ-S-triggered exocytosis is Ca²⁺ independent.

A, intracellular dialysis of GTP-γ-S triggered exocytosis even in the presence of intracellular Ca²⁺ chelator. The pipette solution contained 200 μM GTP-γ-S and 10 mM BAPTA. At time zero, the whole-cell recording began. B, no exocytosis could be observed when the pipette solution contained BAPTA but no GTP-γ-S. C, the amount of exocytosis is dependent on the concentration of GTP-γ-S. The pipette solution contained 0, 50, 200 or 500 μM GTP-γ-S. Each data point is generated from 4-13 cells. Note that at [GTP-γ-S] > 200 μM, the effect of GTP-γ-S appeared to saturate at ≈0.5 pF.