SynGAP still associates with the PSD in Psd-95^−/− mice. Western blotting for PSD components in homogenates of S1 cortex reveals a dramatic increase in PSD components during the first postnatal week (a). b, Western blotting for NR1, CaMKII, PSD-95, and SynGAP (Syn) in homogenates, synaptosomes, and PSDs isolate from S1 of P7 WT mice as well as SynGAP expression in the PSD of P7 Psd-95^−/− mice. n.d., Not done.