Kiss and run exocytosis of dense core secretory vesicles

The mechanisms by which large, dense core, peptide-containing vesicles release their cargo from neuroendocrine cells has been the subject of intense debate during the past few years. Thanks to recent studies of the vesicle membrane post fusion, the view that exocytosis is obligatorily linked to the complete collapse of these vesicles at the cell surface is gradually being revised. We discuss here the evidence supporting a model in which (1) exocytosis and endocytosis of dense core vesicles are closely coupled, and (2) the release of peptides occurs from largely intact vesicles via the formation of a large, but transient, fusion pore.