Nucleus accumbens D1- and D2-expressing neurons control the balance between feeding and activity-mediated energy expenditure

Accumulating evidence points to dysregulations of common brain systems in eating disorders (ED), the Nucleus Accumbens (NAc) in particular. However, to which extent alterations in NAc activity contribute to ED-like dimensions remains unclear. Using chemogenetic manipulations of dopamine D1 receptor-expressing and D2-expressing neuronal subpopulations of the NAc in male mice, we assessed their respective roles in incentive processes, food intake and the balance between feeding and exercise-mediated energy expenditure. We found that D1-neurons facilitate effort for a food reward but decreased food intake, while D2-neurons have opposite effects. The anorexigenic influence of D1-neurons was accompanied by increased voluntary exercise while the orexigenic effect of D2-neurons was concomitant with decreased running, congruent with D2-neurons being more active than D1-neurons during feeding while it is the opposite during running. Chronic manipulations of each subpopulations had limited effects on energy balance. However, repeated activation of D1-neurons combined with inhibition of D2-neurons biased behavior toward activity-related energy expenditure leading to weight/fat loss, whilst the opposite manipulations favored energy intake and hence weight/fat gain. Strikingly, concomitant activation of D1-neurons and inhibition of D2-neurons precipitated weight loss in anorexia models. These results suggest that dysregulations of NAc dopaminoceptive neurons might be at the core of EDs.