Regional density of monoamine-accumulating amacrine cells in the rabbit retina.

The spatial distribution of noradrenaline (NA)- and indoleamine-accumulating (IA) amacrine cells was studied by fluorescence microscopy in flatmounts and tangential cryosections (15 microns thickness) of albino rabbit retinas. The two classes of cells were found to be distributed over the retinal field in a mixed and random fashion. The regional density (mean +/- S.D. cells/mm2) of monoamine accumulating cells was highest in the visual streak (NA cells, 88 +/- 5; IA cells, 1507 +/- 92), and lowest (41 +/- 7; 625 +/- 105, respectively) in the inferior periphery. The density ratio of NA:IA cells was 1:15 on average. Among cells located in the amacrine cell layer, NA and IA cells accounted for 0.3 and 3.9% of the total cell population, respectively. Monoamine-accumulating amacrine cells displaced into the ganglion cell layer were few; these displaced cells were only 2% and 0.6% of the cell number of normally situated cells in the amacrine cell layer for NA and IA cells, respectively.