[Cholinergic chemical transmission. Mechanisms of control]

The isolation of fractions of purified synaptic constituents has permitted to localize the enzymes involved in cholinergic mechanisms and to evaluate the acetylcholine concentration of vesicular stores and of the cytoplasmic pool where transmitter is synthetized. The isolation of cholinergic synaptosomes allowed study the mechanisms and regulations controlling the release process. The depletion of cytoplasmic acetylcholine elicited by stimulation is discussed in parallel to the role of synaptic vesicles. Presynaptic membrane proteins seem to be directly involved in the release of the transmitter.