Cholinesterases of neuromuscular junction.

The ultrastructural localization of AChE and BuChE was studied in motor endplates of the rat and mouse diaphragms, using the CNS(?) modification of the one-step Cu-thiocholine procedure. AChE activity was observed on pre- and postsynaptic membranes, in the basal lamina and in the Schwann cell-nerve terminal interspace. The localization of BuChE was similar but much less pronounced in the adult muscle, while for the developing muscle, the reverse was true.