Figure 4

Effects of age on protein expression of NMDA receptor subunits in crude synaptosomes. A: Representative bands from crude synaptosomes prepared from cortex and labelled with an antibody specific for the ε2 subunit. To the right are bands from different μg loads of caudal cortex used to obtain a standard curve. Five different μg amounts of caudal cortex were loaded as standards for each blot. To the left are representative bands from the prefrontal/frontal (P/F) cortex of a 3 (3 mo) and 26 (26 mo) month old mouse. B: Representative bands for all other proteins analyzed in crude synaptosomes from prefrontal/frontal cortex and hippocampus. Columns show labelling of different proteins from the same animal and well. Each well was loaded with 3 μg of crude synaptosomes. C, D: Graphs of protein expression of the ζ1, ε1, and ε2 subunits of the NMDA receptor and syntaxin in 3 and 26 month old mice, expressed as μg caudal cortex equivalents/μg protein loaded, in prefrontal/frontal cortex (C) and hippocampus (D). * p < .05 for difference from 3 month old mice (analysis of variance and Fisher's protected least significant difference post-hoc analysis). n = 8 for 3 month olds and n = 6 for 26 month old mice for prefrontal/frontal cortex. n = 6 for both ages for hippocampus. Error bars represent SEM.