EphrinB/EphB Signaling Contributes to the Synaptic Plasticity of Chronic Migraine Through NR2B Phosphorylation.

The specific mechanism of migraine chronification remains unclear. We previously demonstrated that synaptic plasticity was associated with migraine chronification. EphB receptors and their ligands, ephrinBs, are considered to be key molecules regulating the synaptic plasticity of the central nervous system. However, whether they can promote the chronification of migraine by regulating synaptic plasticity is unknown. Therefore, we investigated the role of ephrinB/EphB signaling in chronic migraine (CM). Male Sprague-Dawley rats were used to construct a chronic migraine model by dural infusion of an inflammatory soup for 7 days. We used qPCR, western blot, and immunofluorescence to detect the mRNA and protein levels of EphB2 and ephrinB2. The paw withdrawal latency and paw withdrawal threshold were measured after lateral ventricle treatment with EphB1-Fc (an inhibitor of EphB receptor). Changes in synaptic plasticity were explored by examining synaptic-associated proteins by western blot, dendritic spines of neurons by Golgi-Cox staining, and synaptic ultrastructure by transmission electron microscopy. We found that the expression of EphB2 and ephrinB2 increased in CM. The administration of EphB1-Fc relieved hyperalgesia and changes in synaptic plasticity induced by CM. In addition, EphB1-Fc inhibited the upregulation of NR2B phosphorylation. These results indicate that ephrinB/EphB signaling may regulate synaptic plasticity in CM via NR2B phosphorylation, which suggests the novel idea that ephrinB/EphB signaling may be a target for the treatment of migraine chronification.