Insights on retina and optic nerve metabolism during rat aging

Little is known concerning the biochemical response of the various tissue components of the optic pathway to aging. The in vitro incorporation of radioactive precursors into RNA and lipids of whole retina, as well as into glycerophospholipids of optic nerve was tested in male Wistar rats aged 4, 12, and 24 months. The results obtained suggested that RNA metabolism of rat retina (most likely photoreceptor cell layer) was not affected by the age, whereas phospholipid synthesis was on the contrary increased in comparison with that of the optic nerve, for which a serious impairment was observed. The physiological significance of this response, and the mechanism by which retinal tissue is spared from the general age derangement of the nervous system remain to be defined.