| Comments |
P.243 right column bottom paragraph:"Following exocytosis, endocytic structures appeared adjacent to the active zone (Fig. 3 and Fig. 4 Extended Data Fig. 4 for more example electron micrographs). Shallow pits (<40 nm), deep pits (>40 nm), and fully internalized vesicles (>50 nm) were all observed within 50 ms after stimulation and were declining by 300 ms (Fig. 3a–d, i). The number of shallow and deep pits increases again at 1 s, indicating a possible secondary wave of endocytosis. The diameters of these endocytic pits and large vesicles are similar (86 ± 2.4 nm and 82 ± 1.2 nm, respectively), suggesting a precursor–product relationship between these structures (Fig. 3h). The surface area of large vesicles is comparable to the surface area of about four synaptic vesicles (see membrane calculations in Methods). Electron-dense filaments are occasionally visible around these endocytic structures (Extended Data Fig. 4j, k), but they differ from classical coats (Extended Data Fig. 4m–p)." |