Fig. 5. DCV exocytosis in neuronal soma under conditions of strong and weak depolarization. (A) Comparison of release probabilities at high [total number of analyzed vesicles (n)=1091] and low (n=1525; ^***P<0.001) K⁺ stimulation. (B) A representative example of DCV exocytosis in soma under low K⁺ (30 mM) stimulation. The time interval between two consecutive points is 0.1 seconds. (C) Comparison of the fluorescence rise time (t_r) of events at high- and low-K⁺ stimulation (^***P<0.001). (D) Analysis of the content released during exocytosis for DCVs in soma at high (90 mM) and low (30 mM) K⁺ stimulation. The fluorescence loss (F) from a vesicle was calculated from values 2 seconds before and 15 seconds after an event. Gaussian fitting revealed two populations under both stimulation conditions. At low-K⁺ stimulation (broken lines), a larger subset of DCVs exhibited extensive content release compared with DCVs stimulated at high K⁺ (solid lines). A total of 332 fusion events under 90 mM K⁺ stimulation and 90 events under 30 mM K⁺ stimulation were analyzed in C and D.