Increased Incorporation of [3H]Lysine into Synaptic Membranes of the Visual Cortex Following First Exposure of Dark-Reared Rats to Light Is Confined to Particular Polypeptides

Abstract: The incorporation of ³H]lysine into separated polypeptides of synaptic-membrane fractions prepared from the visual cortices of dark-reared rats and littermates exposed to light for 1 h was examined. Increased incorporation of ³H]lysine was found in synaptic membranes from light-exposed compared to dark-reared rats in polypeptides of four molecular weights: 100,000, 71,000, 44,000, and 38,000. The 44,000-molecular-weight peak has been suggested to be actin on the basis of its comigration with pure brain actin. These results indicate that increased incorporation of ³H]lysine into synaptic membranes of the visual cortex, following first exposure of dark-reared rats to light, is confined to particular polypeptides.