G-CSF receptor is expressed in retinal ganglion cells of the rat retina. Robust G-CSFR immunoreactivity was detected in the RGC layer (A-C). RGCs were specifically labelled with the fluorescent tracer Fluorogold in (D). G-CSFR labelling in (E) shows that all RGCs expressed G-CSFR protein. Only faint G-CSFR immunoreactivity was detected in outer retinal layers (A-C). FG: Fluorogold; RGCL: retinal ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; ONL: outer nuclear layer.