Social learning reverses conditioned aversion to nicotine via oxytocin receptor in the infralimbic cortex in rats (839.4)

Abstract

The initial aversive response to cigarettes in most smokers is thought to be ameliorated by the presence of peers who also smoke. We previously reported that social learning (i.e. detecting an odor cue associated with nicotine from peer rats) reversed the development of conditioned taste aversion (CTA) between self‐administered nicotine and a contingent olfactogustatory cue in adolescent rats (PMID:21796102). Herein, we focused on the role of oxytocin in infralimbic cortex (IL) as a mechanism for the effect of social learning. Bilateral lesions of IL before (F1,13=18.1, p=0.001) but not after (F1,16=0.481, p>0.05) self‐administration reduced the effect of social learning on tests of CTA. We also found that carbon disulfide contained in rats’ breath was the signal mediating social learning and its effect also required intact IL. We then infused a specific oxytocin receptor antagonist, desGly‐NH2‐d(CH2)5[D‐Tyr]OVT, (0.028 ~ 2.8 μg/ml, a gift from Dr. Mannings) bilaterally into the IL, which dose‐dependently reduced the effect of carbon disulfide on nicotine CTA (F4,30=3.9, p=0.01). The highest dose of the antagonist had no effect on i.v. saline control rats. These results suggested that the release of oxytocin in the IL is a critical signal that reversed the conditioned aversion between nicotine and its olfactogustatory cue, which in turn enabled voluntary nicotine intake in adolescent rats.Key words: nicotine; aversion; social learning; infralimbic cortex; oxytocin