TABLE 2.
GABA and allosteric modulator sensitivity in wild type and mutant GABA-A ρ1 receptors
Summary of EC50/IC50 and Hill coefficient values for GABA and coapplication amiloride, GMQ, and picrotoxin on the wild-type hGABAA-ρ1, hGABA-A ρ1 T6′F, hGABA-A ρ1 I15′N, and hGABA-A ρ1 N19′D mutant receptors. n ≥ 4 cells.
| Receptor | EC50 | nH | Amiloride EC50/IC50 | Amiloride nH | GMQ IC50 | GMQ nH | PTX IC50 | PTX nH |
|---|---|---|---|---|---|---|---|---|
| μM | μM | μM | μM | |||||
| WT ρ1 | 9.4 ± 0.1 | 1.1 ± 0.2 | (EC50) 77.0 ± 6.3 | 1.6 ± 0.2 | 13.2 ± 0.6 | 1.4 ± 0.1 | 4.8 ± 0.2 | 1.3 ± 0.1 |
| ρ1(T6′F) | 8.0 ± 1.7 | 0.6 ± 0.1 | (IC50) 277.3 ± 88.6 | 1.2 ± 0.3 | 0.4 ± 0.1*** | 0.8 ± 0.2 | N.D. | N.D. |
| ρ1(I15′N) | 2.9 ± 0.6*** | 1.0 ± 0.2 | N.D. | N.D. | 630.5 ± 58.4*** | 1.5 ± 0.2 | 63.4 ± 12.0** | 0.6 ± 0.1 |
| ρ1(N19′D) | 7.4 ± 1.5 | 1.0 ± 0.2 | (IC50) 66.4 ± 9.4 | 0.4 ± 0.02 | N.D. | N.D. | N.D | N.D |
N.D., not determined.
**P < 0.01; ***P < 0.001.