l-Glutamate dose–response properties obtained on coexpression of different ratios of the NR2B wild-type and NR2BE387A mutant subunits with the NR1 subunit
| cRNAs injected | EC50(μm) | nH | Imax(nA) | Fractional current (%) | n |
|---|---|---|---|---|---|
| NR2B | 1.5 ± 0.5 | 1.5 ± 0.2 | 3600 ± 1000 | 9 | |
| NR2B + NR2BE387A (5:1) | 4200 ± 1300 | 3 | |||
| HA-component | 1.3 ± 0.8 | 1.5 ± 0.2 | 872 ± 10 | ||
| IMA-component | 33 ± 19 | 1.3 ± 0.4 | 28 ± 10 | ||
| LA-component | n.d. | ||||
| NR2B + NR2BE387A (1:1) | 2900 ± 400 | 4 | |||
| HA-, IMA-, LA-component | n.d. | ||||
| NR2B + NR2BE387A (1:5) | 2500 ± 900 | 3 | |||
| HA-component | n.d. | n.d. | |||
| IMA-component | 23 ± 13 | 1.2 ± 0.4 | 33 ± 12 | ||
| LA-component | 380 ± 93 | 1.7 ± 0.1 | 67 ± 12 | ||
| NR2BE387A | 363 ± 65 | 1.4 ± 0.2 | 3300 ± 700 | 3 |
NR2B wild-type and mutant cRNAs were coinjected with the NR1 cRNA into Xenopus oocytes at the RNA ratios indicated in parentheses, and l-glutamate responses of the resulting receptors were analyzed by voltage-clamp recording as detailed in Materials and Methods. EC50 values ± SD were calculated from dose–response curves obtained from three to nine oocytes, each. Imax values were determined in the presence of saturating concentrations of l-glutamate and glycine. nH, Hill coefficient; n.d., not detectable. HA, High-affinity; IMA, intermediate-affinity; LA, low-affinity components of mixed receptor populations.