Effects of mutation of α1 subunit His101 on modulation of the α1β2γ2 receptor by FNZ
| α1 Subunit (no. of oocytes) | Ki (from binding studies3-a) | EC50 | Maximum Effect |
|---|---|---|---|
| nM | % of control | ||
| Wild type3-b(5) | 6.12 ± 0.36 | (1) 5.8 ± 1.6 | (1) 256 ± 18 |
| (2) 178 ± 132 | (2) −70 ± 17 | ||
| H101F (4) | 92.8 ± 9.1 | 8.6 ± 1.0 | 290 ± 8 |
| H101Y (4) | 142 ± 2 | 93 ± 19 | 266 ± 12 |
| H101K (3) | No binding | No effect | |
| H101E (4) | No binding | >1 μM | >160% |
| H101Q (4) | 103 ± 11 | 54 ± 49 | 217 ± 16 |
↵3-a Data from Davies et al. (1998), in which wild-type and mutant receptors were expressed in tsA201 cells. Kivalues were obtained in experiments in which FNZ was used to displace [3H]Ro15-4513, which was present at a concentration equivalent to its Kd value for each receptor type.
↵3-b As shown in Fig. 2, a plot of the effects of FNZ had a bell-shaped appearance. The parameters quoted were obtained from curve-fitting as described in the text in which (1) describes the potentiation of GABA-induced currents observed at low FNZ concentrations and (2) describes the inhibitory effect at higher concentrations.