The 3 NMDAR subunits, NR1, NR2A, and NR2B, are expressed in human fetal brain at midgestation. (A) Expression of the genes Grin1 and Grin2a increases with age, while that of Grin2b decreases from the youngest group 15–17 gw to the oldest group 22–24 gw (n = 3 per age group; P < 0.05). The mean values are plotted; the error bars represent ± the SEM. (B) Western blot of the NR1, NR2A, and NR2B subunits across all ages studied. GAPDH is the loading control. (C) Densitometric analysis confirms that NR1 protein expression does not change with age, while NR2A and NR2B protein levels parallel the trend in the expression of their respective genes, with an age-dependent increase in NR2A and decrease in NR2B (n = 3 per age group; P < 0.05). The mean values are plotted; the error bars represent ± the SEM.