Synaptosomes: Different populations storing catecholamines and Gamma-aminobutyric acid in homogenates of rat brain [25]

IT is well established that when brain tissue is homogenized large numbers of nerve terminals pinch off to form intact membrane-bound particles known as "synaptosomes". These can be isolated from brain homogenates by density gradient centrifugation^1-3. Such particles contain various presumptive transmitter substances such as acetylcholine, noradrenaline (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT)^1-3. Knowledge of synaptic organization could be greatly advanced if a differential morphology for nerve terminals using various transmitters could be established. Attempts to separate synaptosomes storing different transmitters, however, have met with only limited success^4-6.