The Organization of Astrocytes in the Goldfish Visual System

The visual system of the goldfish comprises three separate compartments that may be distinguished by their astrocytic populations. The retina contains radial (Muller) glia, which express glial fibrillary acidic protein (GFAP), the optic nerve is characterized by process-bearing astrocytes that express cytokeratins, and the rest of the brain, like the retina, contains radial glia expressing GFAP. In what follows, the author will examine each of these compartments in some detail and discuss the possible functional significance of the region-to-region variation that characterizes the astrocytic population of the goldfish visual system.