Fig. 1

Role of neuroinflammation in the pathogenesis of depression. Low levels of DA can promote the inflammatory reaction, and the produced inflammatory cytokines can increase the probability of depression by reducing the prominent availability of neurotransmitters, increasing neurotoxicity, inhibiting GRs activity, and destroying neurogenesis and synaptic plasticity. ↑: upregulate; ↓: downregulate; ROS reactive oxygen species, RNS reactive nitrogen species, BH4 tetrahydrobiopterin, TDO tryptophan 2,3-dioxygenase, Kyn kynurenine, 5-HT 5-hydroxytryptamine, VMAT2 vesicle monoamine transporter 2, DA dopamine, p38MAPK p38 mitogen-activated protein kinase, MAPK mitogen-activated protein kinase, MAO monoamine oxidase, DRD3 dopamine receptors 3, DRD4 dopamine receptors 4, DRD5 dopamine receptors 5, SystemXc− Cystine/Glu reverse transporter system, Glu glutamate, EAATS excitatory amino acid reuptake transporters, HPA hypothalamus pituitary adrenal, GC glucocorticoid, GRs glucocorticoid receptors, NF-κB nuclear factors-kappa B, STAT5 signal transducer and activator of transcription 5, NGF nerve growth factor, BDNF brain-derived neurotrophic factor, TrkB tropomyosin receptor kinase B, PFC prefrontal cortex