A-C Representative micrographs showing vesicle distribution in type Ib boutons of WT (A), synapsin (−) (B) and rescue (C) genotypes. Note a central core devoid of vesicles in WT and rescue, but not in syanpsin (−) boutons.
D-F. The results of a morphometric analysis show that the area occupied by vesicles in synapsin (−) boutons significantly exceeds that of WT or rescue (Res) boutons (D), while the vesicle density (E) and vesicle numbers (F) are reduced in synapsin (−) boutons. For each line, 3 larvae (22-27 boutons) were used to collect the data.