Distribution of AChE in cholinergic and non-cholinergic neurons.

Intracellular and surface acetylcholinesterase activities were determined for individual cholinergic and non-cholinergic neurons dissected from the central nervous system of the leech. Echothiophate pretreatment was used to inhibit selectively extracellular enzyme. Cells releasing acetylcholine as a transmitters had approximately 10-fold higher levels of intracellular acetylcholinesterase activity, while all neurons had similar levels of activity associated with the cell surface. These results suggest that intracellular cholinesterase may be a useful marker for cholinergic neurons.