Figure 3
Intense stimulation in CAPS DKO neurons triggers relatively more SV than DCV exocytosis. (a) Schematic representation of the method to measure SV exocytosis with synaptophysin-pHluorin (SypHy). Neurons infected with SypHy (left) were stimulated (16 trains of 50 AP at 50 Hz; blue bars) to elicit SV exocytosis, which was detected by appearance of fluorescent puncta (middle). NH4 + supersfusion revealed the total pool of SypHy labeled SVs (right). Lower panels show a zoom of the dotted box in the upper panel. (b) Representative maximal SypHy response during stimulation (Fstimmax) in a neurite of CAPS-2 KO (control) and CAPS DKO neurons. (c) ΔF/Fmax SypHy signal before, during and after stimulation (blue bars) and during and after NH4 + superfusion (yellow bar) in CAPS DKO and control neurons. Shaded area represents SEM. (d) NH4 + max (maximal ΔF/F0 during NH4 + wash) in control and CAPS DKO neurons. Mann-Whitney U test: p = 0.24 (not significant, ns). (e) Fstimmax (peak in the ΔF/Fmax SypHy graph, see c) of control and CAPS neurons. Mann-Whitney U test: p = 0.042 (*). (f) Average DCV exocytosis events in control and CAPS DKO neurons. Data from Fig. 2i, duplicated for clarity. Mann-Whitney U test: p = 2.0 *10−8 (***). Detailed information (average, SEM, n and detailed statistics) is shown in Table S1.
