Influence of uridine-5-monophosphate on 3H-leucine incorporation into hippocampal neurons during learning

The influence of UMP (injected intraventricularly) on the incorporation of ³H-leucine (injected intraperitoneally) was studied in rats using the microautoradiographic technique. Under the conditions of a brightness discrimination, the incorporation of labeled leucine into hippocampal neurons was significantly increased by UMP pretreatment, whereas under control conditions UMP caused only a tendency of increase without any statistical significance. It is suggested, that under learning conditions UMP substitution increases RNA synthesis, which would yield an enhanced protein synthesis.