Abstract
In the rabbit retina acetylcholinesterase activity is localized in the perinuclear cisterna, in the cisternae of the rough surfaced endoplasmic reticulum and in the Golgi apparatus of ganglion cells and amacrine cells. The histochemical reaction is positive also in the rough surfaced endoplasmic reticulum of some horizontal cells. The highest activity is seen in the internal plexiform layer; because of artifacts caused by the diffusion of the enzyme, a clear demonstration of relation of the positivity to one or the other regular components of this layer, however, is not possible. Myelinated fibers which exhibit acetylcholinesterase activity and are most probably efferent are found in the internal plexiform layer. In the retinal nerve fiber layer and in the optic nerve only a few fibers show a positive reaction.