Western blot analysis of young and aged hippocampus shows no change in the expression level of the NMDA receptor 2B (NR2B) but an increase in the phosphorylation state of the NR2B receptor protein at the Ser1303 site in aged mice. A,B) Scatter bar graphs depict quantification of western blot for NR2B relative to tubulin and pNR2B relative to NR2B. C,D,E) Representative western blot images for NR2B, pNR2B, and tubulin. ** indicates p < .01, t-test.