RESUMO
BACKGROUND: Calorie restriction (CR) induces long-term changes in motivation to eat highly palatable food and, in body weight regulation, through an unknown mechanism. METHODS: After a period of CR and refeeding, mice were assessed by behavioral and metabolic studies and for levels of the transcription factor ΔFosB. The ΔFosB levels were then increased specifically in nucleus accumbens (NAc) with viral-mediated gene transfer, and behavioral and metabolic studies were conducted. RESULTS: We show that accumulation of ΔFosB in the NAc shell after CR in mice corresponds to a period of increased motivation for high fat reward and reduced energy expenditure. Furthermore, ΔFosB overexpression in this region increases instrumental responding for a high fat reward via an orexin-dependent mechanism while also decreasing energy expenditure and promoting adiposity. CONCLUSIONS: These results suggest that ΔFosB signaling in NAc mediates adaptive responses to CR.
