Parasol (Pα) ganglion-cells of the primate fovea: Immunocytochemical staining with antibodies against GABA A-receptors

Abstract

Retinae of macaque monkeys were immuno-stained with antibodies against GABA A-receptors. In peripheral retina most ganglion cells were immunoreactive. In central retina, around the fovea, staining in the ganglion cell layer was selective and only 5–8% of all ganglion cells were labelled: these had the largest cell bodies and their dendrites occupied a broad stratum in the middle of the inner plexiform layer. From comparison with Golgi-stained ganglion cells it is concluded that the entire population of parasol (Pα)-cells at the fovea was labelled. The mosaic and sampling properties of parasol cells were determined by combining dendritic field measurements of Golgi-stained cells with their density when immuno-stained. There is convergence of 30–50 cones onto each foveal parasol ganglion cell. The dendritic fields of both ON- and OFF-parasol cells provide complete retinal coverage. The Nyquist limits of their mosaics are 4 min of arc.