Cannabidiol inhibits sucrose self-administration by CB1 and CB2 receptor mechanisms in rodents

A growing number of studies suggest therapeutic applications of cannabidiol (CBD), a recently U.S. Food and Drug Administration (FDA)-approved medication for epilepsy, in treatment of many other neuropsychological disorders. However, pharmacological action and the mechanisms by which CBD exerts its effects are not fully understood. Here, we examined the effects of CBD on oral sucrose self-administration in rodents and explored the receptor mechanisms underlying CBD-induced behavioral effects using pharmacological and transgenic approaches. Systemic administration of CBD (10, 20, and 40 mg/kg, ip) produced a dose-dependent reduction in sucrose self-administration in rats and in wild-type (WT) and CB1^-/- mice but not in CB2^-/- mice. CBD appeared to be more efficacious in CB1^-/- mice than in WT mice. Similarly, pretreatment with AM251, a CB1R antagonist, potentiated, while AM630, a selective CB2R antagonist, blocked CBD-induced reduction in sucrose self-administration, suggesting the involvement of CB1 and CB2 receptors. Furthermore, systemic administration of JWH133, a selective CB2R agonist, also produced a dose-dependent reduction in sucrose self-administration in WT and CB1^-/- mice, but not in CB2^-/- mice. Pretreatment with AM251 enhanced, while AM630 blocked JWH133-induced reduction in sucrose self-administration in WT mice, suggesting that CBD inhibits sucrose self-administration likely by CB1 receptor antagonism and CB2 receptor agonism. Taken together, the present findings suggest that CBD may have therapeutic potential in reducing binge eating and the development of obesity.