WHAT DO THE SYNAPTIC VESICLES CONTAIN

The intersynaptic membranes of the rat brain cortex were found to remain firmly attached to one another after perfusion of strongly anisotonic solutions. Brains perfused with depolarizing and excitotoxic agents showed abundant, apparent intermingling of mitochondria and synaptic vesicles. The results suggest (i) that the intersynaptic membranes are not separated from one another by an essentially fluid intersynaptic medium as it is commonly assumed, but rather firmly attached to one another by a layer of faintly osmiophilic yet remarkably stable, water-insoluble material; and (ii) that the synaptic vesicles may be involved in adenosine triphosphate carriage. Well established multidisciplinary data are presented which appear to be in line with both possibilities.