Ultrastructural localization of acetylcholinesterase activity in the developing chick retina.

Abstract

Acetylcholinesterase (AChE) activity in the developing chick retina was histochemically studied by EM. The enzyme activity in the 1 day old chick retina was confined within the ganglion, amacrine and horizontal cells as well as in the inner plexiform layer. In the inner plexiform layer reaction product was found in the intercellular spaces between nerve processes. Synapses in this layer did not always display reaction product. In the developing chick retina, AChE activity was found in the innermost layer of 6 day old retina in ovo. The stage of the appearance of histochemically demonstrable AChE activity in the developing ganglion and amacrine cells mostly coincided with that of the beginning of morphological maturity of these cells. Apparently, the ganglion, amacrine and horizontal cells are functionally different from other types of neurons, and synthesis of the enzyme starts at almost the same time as those cells begin to manifest the morphological characteristics of each cell type.