Choline acetyltransferase: regional distribution in the abdominal ganglion of Aplysia.

Using a new microassay, we have determined the properties and the regional distribution of choline acetyltransferase in the abdominal ganglion of Aplysia. Enzyme concentrations in homogenates of groups of cells and in single identified cells indicate that neurons which function as neurosecretory cells, and which do not form chemical synapses with other cells or with peripheral structures, have little or no ability to synthesize acetylcholine; neurons which are involved in visceromotor integrations, and which connect with each other or with the periphery, have a substantial concentration of the enzyme.