Shape and distribution of astrocytes in the cat retina.

Astrocytes in the adult cat retina were stained by immunocytochemical localization of glial fibrillary acidic protein (GFAP), a major constituent of the astrocytic intermediate filaments. Their density in whole mounted retinae showed a peak of about 2000 astrocytes/mm2 at the optic nerve head and dropped to approximately 200 astrocytes/mm2 in the far periphery. At the central area a prominent local minimum of astrocyte density was found. The shape of astrocytes changed from a stellate form in the outermost retinal periphery to an elongated form in the central part of the retina with the majority of astroglial processes aligned in parallel with the ganglion cell axons. Results in the cat retina suggest a close correlation between astrocytes and optic nerve fibers, the latter presumably being involved in the establishment of the astrocytic network.