SEPARATION OF ACETYLCHOLINE AND CATECHOLAMINE CONTAINING SYNAPTIC VESICLES FROM BRAIN CORTEX

Abstract— Synaptic vesicles were prepared from guinea-pig cerebral cortex on a continuous D₂O-H₂O(1:1)-sucrose gradient and purified in the presence of 1 m m -EGTA by chromatography on columns of glass beads of controlled pore size. As markers, endogenous ACh, NA, dopamine and DβH were measured.
Two distinct populations of synaptic vesicles were recognized between the layers of 0.2–0.3 m - and 0.3–0.5 m -sucrose, which differed from each other both in electron microscopic appearance and transmitter content. The less dense vesicles had a much higher ACh content than the more dense vesicles which were composed mainly of somewhat larger particles with high NA and dopamine content. DβH was found to be present in substantial amounts in guinea-pig cortex and was located in the synaptic vesicle fractions having high CA content.
After glass bead chromatography the vesicle preparations were morphologically homogeneous, practically free from other subcellular elements and were contaminated with each other by not more than 10%
The yields were 0.2 and 0.1 mg protein g cortex⁻¹ tissue for 'cholinergic' and 'adrenergic' vesicle preparations, respectively.