DIFFERENTIAL MODULATION OF BRAIN IMMEDIATE-EARLY GENES BY INTRAPERITONEAL LICL

WE have used in situ hybridization to investigate the modulation of ex pression of the immediate early genes (IEGs) c-fos, fos-B, zif/268 and CREM in rat brain following oral administration of saccharin, i.p. in jection of LiCl, and conditioned taste aversion (CTA) training in whic h these stimuli are used as the conditioned stimulus (CS) and the unco nditioned stimulus (UCS), respectively. Modulation of c-fos, zif/268 a nd CREM was detected in the NTS, PBN, hypothalamic PVN and central nuc leus of the amygdala after the administration of the UCS but not the C S. Our data are consonant with the hypothesis that differential and co mbinatorial expression of IEGs plays a role in encoding the representa tion of LiCl-induced malaise in the brain.