Sensitivity of mutant NMDA receptors to glutamate and glycine
| Subunit combination | Glutamate | Glycine | Imax | ||
|---|---|---|---|---|---|
| EC50 | n | EC50 | n | ||
| μm | μm | nA | |||
| Wild-type NR1a/NR2B | 1.53 (1.37, 1.71) | 8 | 0.15 (0.14, 0.16) | 8 | 630 ± 119 |
| NR1a(W563L)/NR2B | 0.28 (0.25, 0.31)1-b | 4 | 0.04 (0.03, 0.06)1-b | 4 | 156 ± 191-a |
| NR1a(W608L)/NR2B | 0.70 (0.64, 0.77)1-b | 5 | 0.12 (0.11, 0.13) | 6 | 624 ± 96 |
| NR1a(W611L)/NR2B | 0.92 (0.86, 0.99)1-b | 5 | 0.12 (0.11, 0.12) | 6 | 543 ± 117 |
| NR1a(N616Q)/NR2B | 0.25 (0.24, 0.26)1-b | 5 | 0.04 (0.03, 0.05)1-b | 6 | 162 ± 151-a |
| NR1a(N616G)/NR2B | 0.95 (0.89, 1.01)1-b | 5 | 0.12 (0.11, 0.13) | 5 | 298 ± 83 |
| NR1a(N616R)/NR2B | 0.83 (0.77, 0.90)1-b | 5 | 0.10 (0.10, 0.11)1-b | 6 | 239 ± 411-a |
| NR1a(S617N)/NR2B | 1.98 (1.95, 2.01) | 5 | 0.15 (0.14, 0.17) | 5 | 817 ± 1861-a |
| NR1a(E621Q)/NR2B | 1.58 (1.45, 1.74) | 5 | 0.17 (0.17, 0.18) | 6 | 146 ± 19 |
| NR1a(Y647L)/NR2B | 0.33 (0.28, 0.39)1-b | 5 | 0.04 (0.03, 0.04)1-b | 6 | 231 ± 50 |
| NR1a/NR2B(W559L) | 2.89 (2.20, 3.79)1-b | 4 | 0.11 (0.10, 0.12) | 4 | 196 ± 261-a |
| NR1a/NR2B(W607L) | 2.48 (2.36, 2.60)1-b | 4 | 0.22 (0.21, 0.23) | 4 | 329 ± 951-a |
| NR1a/NR2B(W610L) | 2.07 (1.95, 2.20) | 4 | 0.15 (0.15, 0.16) | 5 | 768 ± 1531-a |
| NR1a/NR2B(N615Q) | 1.49 (1.42, 1.56) | 4 | 0.10 (0.09, 0.10)1-b | 4 | 777 ± 363 |
| NR1a/NR2B(N616Q) | 1.17 (1.06, 1.29) | 6 | 0.11 (0.10, 0.12) | 4 | 770 ± 242 |
| NR1a/NR2B(Y646L) | 0.82 (0.74, 0.91)1-b | 7 | 0.09 (0.08, 0.10)1-b | 5 | 85 ± 111-a |
EC50 values for glutamate and glycine were determined from concentration-response curves at wild-type and mutant NMDA receptors in oocytes voltage-clamped at −70 mV. Concentration-response curves for glutamate were carried out in the presence of 10 μmglycine, and those for glycine were carried out in the presence of 10 μm glutamate. The maximum response to glutamate and glycine (Imax) in the same experiments is also shown.
↵1-a These oocytes were injected with a 2–10-fold greater amount of cRNA than wild-type oocytes. EC50 values are the geometric mean (−standard error, +standard error), and Imax values are the arithmetic mean ± standard error.
↵1-b p < 0.05 compared with wild-type NR1a/NR2B (one-way analysis of variance withpost hoc Dunnett’s test). n, number of oocytes.