Matching populations of amacrine cells in the inner nuclear and ganglion cell layers of the rabbit retina

Abstract

In rabbit retina, neurofibrillar methods stain two populations of amacrines whose cell bodies are located on either side of the inner plexiform layer: on in the ganglion cell layer and the other at the inner margin of the inner nuclear layer. The stained amacrines in the ganglion cell layer have the distinctive cytology of ‘coronate’ amacrines described from Nissl‐stained retina (Vaney, 1980a) and account for about 85% of the displaced amacrines in the rabbit retina. The coronate amacrines have a streak topography similar to that of the ganglion cells; they comprise about 32% of the neurons in the ganglion cell layer although their proportion increases with eccentricity from the visual streak. The cytology of the neurofibrillar stained amacrines in the inner nuclear layer resembles that of the displaced amacrines and their densities are almost equal. The cell bodies of the stained amacrines are smaller than those of the displaced amacrines but larger than most others in the inner nuclear layer; they account for some 2% of the neurons in the amacrine sublayer. Although the cell bodies of both populations are distributed rather evenly, the mosaic of the inner nuclear layer cells is more regular than that of the ganglion layer cells. We propose that the two populations of amacrines stained by neurofibrillar methods correspond to the acetylcholine synthesizing cells labelled by Masland and Mills (1979).