Ultrastructural localization of acetylcholinesterase in retino-deprived optic tectum of the goldfish.

The ultrastructural localization of AChE has been studied in the optic tectum of the goldfish after unilateral eye ablation. 1 or 4 months after the operation the patterns of enzyme localization were essentially the same in the normal and affected optic tectum, despite structural modifications caused by the degeneration of retinal terminals and dendritic atrophy of some tectal neurons. The results are discussed in relation to the different hypotheses put forward concerning possible cholinergic mechanisms in the optic tectum of teleosts.