NTN1 and Alzheimer disease: In our study, we observed that NTN-1 significantly improved learning and memory behavior in the water maze task, which was consistent with a previous study, and significantly inhibited microglial proliferation and activation in Aβ1-42-induced AD rats, indicating that exogenous NTN-1 treatment attenuated Aβ-induced neurological impairments in memory and learning, which may be due to M1 microglial activation in AD rats.