Displaced Amacrine Cells of the Mouse Retina

Abstract

Purpose:: The aim of this study was to characterize and classify the displaced amacrine cells in the mouse retina.

Methods:: Amacrine cells in the ganglion cell layer were injected with fluorescent dyes in flat-mounted retinae. Dye-filled displaced amacrine cells were classified according to dendritic field size, horizontal and vertical stratification patterns, and general morphology

Results:: We identified ten different morphological types of displaced amacrine cells. Four of these types were characterized as medium-field, with dendritic field diameters of 200-500 µm; six types were characterized as wide-field, with dendritic fields extending over 500 µm. Displaced amacrine cells with dendritic field diameters smaller than 200 µm were not encountered. The most frequently-labeled displaced amacrine cell type was the starburst amacrine cell. None of the ten displaced amacrine cell types showed glycine immunoreactivity, suggesting that displaced amacrine cells are GABAergic. At least three cell types identified here have non-displaced counterparts in the inner nuclear layer as well. Four of the displaced amacrine cell types identified here have been described previously in other species.

Conclusions:: Displaced amacrine cells display a rich variety of stratification and branching patterns which surely reflect the wide range of their functional roles in the processing of visual signals in the inner retina.

Keywords: retina • injection • retina: proximal (bipolar, amacrine, and ganglion cells)