Tat-NR2B9c (Tat-NR2Bct; NA-1) is a postsynaptic density-95 (PSD-95) inhibitor, with EC50 values of 6.7 nM and 670 nM for PSD-95d2 (PSD-95 PDZ domain 2) and PSD-95d1, respectively. Tat-NR2B9c disrupts the PSD-95/NMDAR interaction, inhibiting NR2A and NR2B binding to PSD-95 with IC50 values of 0.5 μM and 8 μM, respectively. Tat-NR2B9c also inhibits neuronal nitric oxide synthase (nNOS)/PSD-95 interaction, and possesses neuroprotective efficacy.