NBTA is a specific blocker of the NMDA receptor. Blocking activity of
NBTA (1 μM) on NMDA receptors (A) or GluR1 channels
(B). (C) Concentration-inhibition curves
for NMDA receptors and GluR1 channels by NBTA (▪), memantine
(▴), MK-801 (▾), or phencyclidine
(●). (D) Blocking activity of NBTA
on wild-type NMDA receptors [NR1/NR2A (■)] −
IC50 = 80 ± 10 nM (n = 6),
and nH = 0.8 and indicated mutants:
N616R/NR2A (⧫) − IC50 = 22,000 ± 1,320
nM (n = 5), nH =
0.8; N616Q/NR2A (○) − IC50 =
240 ± 20 nM (n = 4),
nH = 0.8; NR1/W606L
(▾) − IC50 = 380 ± 32 nM
(n = 5), nH = 0.8;
NR1/N614G (▵) − IC50 = 95 ±
11 nM (n = 5), nH =
0.9; NR1/N615G (□) − IC50 = 72
± 8 nM (n = 5), nH
= 0.9; NR1/S616G (▴) − IC50 =
98 ± 9 nM (n = 5),
nH = 0.8; and N616Q/N614G
(●) − IC50 = 244 ±
23 nM (n = 5), nH =
0.8. Currents were elicited by 200 μM Glu/20 μM Gly at a holding
potential of −80 mV.