Neuronal locus of enhanced incorporation of 3H-lysine into acid insoluble material in visual cortex on first exposure of rats to light

Abstract

Incorporation of 3H-lysine into acid insoluble material of cell fractions derived from the visual cortex of dark reared and light exposed rats was compared. There was an elevation of incorporation of 35% in the whole cell suspension and 33% in the neuronal fraction but only 3% in the neuropil fraction. The ratio of incorporation of precursor into protein in the neuronal fraction of the dark reared animals to that in the neuropil was 63%; after 60 min light exposure the ratio was 93%; in normal animals the ratio was 137%. These observations suggest two hypotheses; that the elevation of protein synthesis in the visual cortex on first exposure to light, is primarily a neuronal phenomenon; and that in the absence of functional stimulation neuronal protein synthesis is depressed and glial protein synthesis elevated compared with the normal controls.