ANPEP and major depressive disorder: To investigate whether AdipoRon displayed similar anti-inflammatory properties to ApN, the concentration of proinflammatory cytokines (IL1β, IL6, TNFα, IFNγ) in various brain regions involved in depression (i.e. hypothalamus, hippocampus, and prefrontal cortex) was measured using a multiplex assay (Fig. 3a).