[Histochemical localization of acetylcholinesterase in the chick ciliary ganglion during development]

The ultrastructural localization of AChE activity has been investigated in the chick ciliary ganglion during embryonic development. Such activity first appears in a relatively early embryonic stage, i.e. at the 6th day of incubation, in the differentiating cisternae of the rough endoplasmic reticulum. In the period between 10 and 15 days of incubation, the reaction product progressively increases extending to other neuronal areas as Golgi complexes, the perinuclear cisterna and some rare areas of the plasma membrane. In particular a certain amount of AChE appears to occur at the neuronal surface where it is contacted by calyciform synaptic nerve endings. This is conceivably to correlate with the morpho-functional maturation of ganglionic synapses.