NMDAR HDAC-IN-1 (Compound 9d) is a potent dual inhibitor of N-methyl-D-aspartate receptors (NMDARs) and histone deacetylases (HDACs). It exhibits a high affinity (Ki = 0.59 μM) for NMDARs, while demonstrating significant inhibitory effects on various HDAC isoforms, including HDAC1, HDAC2, HDAC3, HDAC6, and HDAC8 with IC 50 values of 2.67 μM, 8.00 μM, 2.21 μM, 0.18 μM, and 0.62 μM, respectively. Moreover, NMDAR HDAC-IN-1 efficiently crosses the blood-brain barrier [1].
Tat-NR2BAA is an inactive control peptide of Tat-NR2B9c. It shares a similar sequence with Tat-NR2B9c, but possesses a double-point mutation in the COOH terminal tSXV motif. This mutation renders Tat-NR2BAA unable to bind PSD-95. Tat-NR2B9c, on the other hand, is a membrane-permeable peptide that interferes with PSD-95 NMDAR binding. This interference leads to the decoupling of NR2B- and or NR2A-type NMDARs from PSD-95[1][2].