The potential antidepressant and antidiabetic effects of galanin system

• Activating central GalR2 has antidepressant effect.
• Activating central GalR2 attenuates insulin resistance.
• GalR2 agonist may treat depression and type 2 diabetes mellitus.

Epidemiological and clinical studies demonstrated that type 2 diabetes mellitus and depression are interconnected. Depression is an important risk factor for the development of type 2 diabetes mellitus, while patients with type 2 diabetes mellitus frequently have depressive symptoms. Despite many studies recently probed into the comorbid state of both diseases, so far the precise mechanism for this association is poorly understood. Experiments have demonstrated that neuropeptide galanin is involved in the pathogenesis of depression and type 2 diabetes mellitus. This review provides a new insight into the multivariate relationship among galanin, depression and type 2 diabetes mellitus, highlighting the effect of galanin system on the cross-talk between both diseases in human and rodent models. The current data support that activating central GalR2 attenuates insulin resistance and depressive feature in animal models. These may help us better understand the pathogenesis of both diseases and provide useful hints for the development of novel therapeutic approaches, i.e. to coadministrate GalR2 agonist with traditional antidepressive and antidiabetic medicines to treat depression and type 2 diabetes mellitus.