GRIN2B and Alzheimer disease: Consistently, in SAMP8 mice or AD models injected with Aβ25−35 or Aβ1−42, the expression of NMDAR1, NMDAR2A, and NMDAR2B were decreased markedly in the hippocampus or cortex (Xu et al., 2016; Wang K. et al., 2018; Chang et al., 2020).