Today, there is back and forth debate over full fusion and kiss-and-run fusion and which model portrays a more accurate picture of the mechanisms behind synaptic release. The increased accumulation of partially empty secretory vesicles following secretion, observed in electron micrographs are the most compelling evidence in favor of the kiss-and-run model. Accumulation of partially empty vesicles following secretion suggests that during the secretory process, only a portion of the vesicular contents are able to exit the cell, which could only be possible if secretory vesicles were to temporarily establish continuity with the cell plasma membrane, expel a portion of their contents, then detach and reseal.
