Nanovesicles at sites of multigranular exocytosis. Examples of nanovesicles are shown in digital slices through electron tomograms recorded from secretagogue-challenged HUVECs. (A) 2 WPBs are connected via a nanovesicle (arrowhead). WPBs are indicated by asterisks. The WPBs are in proximity of a secretory pod (SP) that is only partially shown. A seemingly solitary nanovesicle is indicated with an arrow. (B) Adjacent slice through the same tomogram as in panel A, showing a third nanovesicle (arrow) in contact with a WPB. This nanovesicle is also connected to the nanovesicle that appears solitary in panel A. (C) 4 WPBs in proximity of a secretory pod (SP), and interconnecting via 3 nanovesicles (arrows). Scale bars represent 100 nm.