Moreover, D2 dopamine receptors have been implicated in the susceptibility for reward seeking behaviors including predisposition to diet-induced obesity (with high-sugar palatable diets) and drug addiction, probably through a mechanism of sensitization of the reward system in which the signaling of the D2 receptors is altered by the sustained increase of the release of dopamine in the NAcS (Hajnal et al., 2008). This evidence concerns the gene DRD2 and obesity due to melanocortin 4 receptor deficiency.