GluN2 Subunit | Inhibition τMK-801 | Rate of Block 1/τMK-801 | Cells | Estimated Popen | Fold Change in Popen (Relative to Wild Type) |
---|---|---|---|---|---|
ms | s−1 | n | |||
GluN2A | 71 ± 9 | 15 ± 2 | 6 | 0.48a | — |
2A-(2D ATD) | 374 ± 98 | 3.3 ± 0.6 | 6 | 0.10 | 0.22 |
2A-(2D S1) | 199 ± 37 | 5.8 ± 1.0 | 5 | 0.18 | 0.38 |
2A-(2D S2) | 266 ± 25 | 3.2 ± 0.4 | 5 | 0.12 | 0.26 |
2A-(2D S1+S2) | 308 ± 46 | 3.5 ± 0.3 | 7 | 0.11 | 0.23 |
GluN2D | 1043 ± 98 | 1.0 ± 0.1 | 6 | 0.012a | — |
↵a Indicates previously published Popen values for wild-type receptors determined using single-channel recordings (Yuan et al., 2009). To allow comparison with these values, the inhibition data were generated using the same compositions of intracellular and extracellular solutions as the previous study (i.e., pH 8.0 and 0.5 mM Ca2+ in the extracellular solution). The rate of MK-801 inhibition at pH 8.0 was lower than previously described rates at pH 7.6, consistent with MK-801 having a pKa of 8.37 (i.e., less protonated MK-801 at higher pH) (Dravid et al., 2007). All chimeras were blocked > 95% by 5 µM MK-801.