Incorporation of Uridine into Polysomes of Mouse Brain during Extinction

Abstract

MICE injected with radioactive uridine in a double isotope labelling technique and then trained for 15 min to avoid a shock by jumping to a shelf incorporated about 50% more radioactivity into brain RNA¹ and polysomes² than untrained mice yoked to them. Quiet mice, yoked mice, and mice that were subjected to thirty electric shocks at random intervals for 15 min all incorporated less radioactive uridine into brain RNA and polysomes than did the trained mice^1,2. This indicates that the lights, buzzers, shocks, handling and activity have little effect.