Fig. 12

The antidepressant-like effect of taVNS may be related to the regulation of α7nAchR/NF-κB signal pathway. The α7nAChR is the pivotal receptor that mediates the inflammation reflex of the vagus nerve. TaVNS stimulates ABVN, and the brain receives information from the vagus afferent fibers. The afferent fibers project to the NTS in the brainstem, and then form indirect ascending projections from the NTS to hippocampus. TaVNS can affect hippocampus anti-inflammation mediated by α7nAChR on microglia. Hippocampal microglial cells at resting state do not exhibit activation for inflammatory signal pathway. This means that NF-κB signal pathway remains inactivate. However, in pathological condition, the degradation of IκB protein unmasks NF-κB from inactive to active state and the active NF-κB leads to nuclear translocation. NF-κB p65 occurs nuclear translocation to regulate the IL-1β