SUR | Conditions | HMR 1883Ki | GBCKi | Selectivity1-cGBC/HMR | |
---|---|---|---|---|---|
Radioligand1-a | MgATP1-b | ||||
mM | μM | μM | |||
SUR1 | [3H]GBC | 1 | 63 (58, 69) | 0.0015 (0.0013, 0.0018) | 4 × 104 |
0 | 9.5 (7.9, 11.5) | 0.00022 (0.00013, 0.00038) | 4 × 104 | ||
SUR2A | [3H]P1075 | 1 | 14 (12, 16) | 0.50 (0.40, 0.63) | 28 |
1 +ARS | 4.4 (3.8, 5.0) | 0.23 (0.22, 0.24) | 19 | ||
0.003 | 1.8 (1.3, 2.5) | 0.12 (0.10, 0.15) | 15 | ||
SUR2B | [3H]P1075 | 1 | 44 (36, 52)1-d | 2.8 (2.5, 3.1) | 15 |
1 +ARS | 20 (19, 21)1-d | 0.91 (0.69, 1.20) | 22 | ||
0.003 | 4.2 (3.6, 4.8) | 0.59 (0.47, 0.74) | 7 |
↵1-a [3H]Glibenclamide concentration was ∼1 nM; [3H]P1075, ∼3 nM (SUR2A) or 2 nM (SUR2B). The KD values of [3H]P1075 binding used for the Cheng-Prusoff correction were, respectively, for SUR2A (1 mM MgATP/1 mM MgATP + ATP-regenerating system/3 μM MgATP): 15.1/12.9/17.4 nM and for SUR2B: 4.4/2.1/7.8 nM.
↵1-b ARS, ATP-regenerating system. For composition of solutions, see Fig. 2.
↵1-c Selectivity ratio =Ki (HMR)/Ki (GBC).
↵1-d Hill coefficients were:nH = 1.24 ± 0.01/1.35 ± 0.05 for 1 mM ATP/1 mM ATP + ARS, respectively; these values are significantly (P < 0.01) different from 1.0.