Steroid modulation of concatameric receptors with no intact GABA-binding sites, activated by pentobarbital
The table shows the effect of coapplication of 1 μM allopregnanolone with a submaximal concentration of pentobarbital. Given are the effect of steroid (mean ± S.D.) in the presence of a low concentration (100–400 μM) of pentobarbital (1 stands for no effect) (third column) and the ratio of the peak response to a low concentration of pentobarbital and the tail current after the application of 2 mM pentobarbital (fourth column).
| Receptor | Configuration | Potentiation by Allopregnanolone | Fractional Pentobarbital Response | No. of Cells |
|---|---|---|---|---|
| β*αγ-β*α | –S/–S | 6.9 ± 1.7 | 0.20 ± 0.07 | 4 |
| β*αγ-β*α* | –S/– – | 4.8 ± 1.2 | 0.25 ± 0.10 | 5 |
| β*α*γ-β*α | – –/–S | 6.6 ± 1.5 | 0.14 ± 0.06 | 4 |
| β*α*γ-β*α* | – –/– – | 1.2 ± 0.3 | 0.21 ± 0.06 | 4 |
β*, β(Y205S); α*, α(Q241L); S, intact steroid site.