Distribution of D-Aspartate-Immunopositive Cells in the Ganglion Cell Layer of Adult Rat Retina

Background/Aims:D-aspartate is an important candidate for retinal neurotransmitter or neuromodulator. The purpose of this study was to investigate the cells type and distribution of the D-aspartate-immunopositive cells in the ganglion cell layer. Methods: Wister rats were fixed by perfusion with 5% glutaraldehyde. Paraffin sections of the retina were immunohistochemically double-labeled using D-aspartate and glutamate or γ-aminobutyric acid antibodies. After labeling the whole-mount retina by D-aspartate, the cell densities of both the perivascular and nonperivascular areas in the ganglion cell layer were measured for the central, midperipheral, and peripheral zones, respectively. Results: Within the paraffin section, some of the glutamate-immunoreactive cells in the ganglion cell layer were D-aspartate immunoreactive. These D-aspartate-positive cells in the ganglion cell layer were more frequently observed along the retinal vessels in the whole-mount retina. The D-aspartate-positive cell densities in the perivascular area were significantly higher than those in the nonperivascular area for the central, midperipheral, and peripheral zones (p < 0.0001). Conclusion: In the ganglion cell layer, the D-aspartate-immunopositive cells proved to be the ganglion cells, with their distribution found to be denser along the large retinal vessels such as the arterioles or venules.