Anandamide and sucralose change ΔFosB expression in the reward system.

Food reward has been studied with highly palatable stimuli that come from natural additives such as sucrose. The most common food additive is sucralose, a noncaloric sweetener present in many food products of daily intake. The role of anandamide [N-arachidonylethanolamide (AEA)], an endogenous cannabinoid, has been widely studied in food behavior. Studies have shown that cannabinoids, such as AEA, 2-Arachidonilglycerol, and Tetrahydrocannabinol, can provoke hyperphagia, because they enhance the preference and intake of sweet and high-fat food. Taste perception is mediated by receptors taste type 1 receptor 3 (T1R3); therefore, there could be a synergistic effect between receptors CB1 and T1R3. This could explain why cannabinoids could change sweet taste perception and therefore the activity of neural nuclei involved in taste and reward. In this study, we evaluated the activity of dopaminergic nuclei implicated in food reward after the chronic administration of AEA (0.5 mg/kg bw) and sucralose intake (0.02%). We analyzed the expression of ΔFosB by immunohistochemistry. Our results show that the chronic administration of AEA and sucralose intake induces an overexpression of ΔFosB in the infralimbic cortex (Cx), nucleus accumbens (NAc) core, shell, and central nucleus of amygdala (Amy). These results suggest that the possible interaction between receptors CB1 and T1R3 has consequences not only in taste perception but also that AEA intervenes in the activity of dopaminergic nuclei such as the NAc, and that the chronic administration AEA and sucralose intake induce long-term changes in the reward system.