Secretory vesicle-specific antibodies in the confocal study of exo-endocytosis dynamics

The study of secretory vesicle dynamics is a continuing challenge. Classica lly it was studied using biochemical techniques, such as subcellular fracti onation and immunoprecipitation, combined with time-consuming electron micr oscopy studies. The recent development of confocal microscopy, giving in-fo cus optical section images throughout the thickness of a fluorescently labe led sample, allows scientists to study the key events in the secretory cycl e at the level of light microscopy. This study demonstrates the use of spec ific antibodies against marker proteins of two different secretory vesicles (synaptic vesicles and large dense-cored vesicles) to follow their exo-end ocytosis dynamics in peripheral adrenergic neurons. Only in recent years ha s insight grown regarding the presence of both exocytosis pathways in the s ame neuron. Confocal microscopy is a suitable technique to study aspects of exocytosis, endocytosis, and intracellular sorting and as such improves ou r knowledge on the interaction between both secretory pathways. (C) 1999 Ac ademic Press.