The relationship between complex vesicles, dense-cored vesicles and dense projections in cortical synaptosomes.

Cortical synaptosomes fixed in unbuffered OsO4 and glutaraldehyde have been block-stained with phosphotungstic acid (PTA) in order to investigate the relationship between complex vesicles and dense projections. It is concluded that the shell of the complex vesicles contributes to the formation of dense projections and that, in addition, there is a correspondence between this shell and the previously described presynaptic network. The process by which complex vesicles become associated with dense projections appears to be accentuated by electrical stimulation of the synaptosomes.