Table 1.
Ethanol and GABA sensitivity for GABARs of different subunit combinationsa
| Percent enhancement by ethanol |
||||||
|---|---|---|---|---|---|---|
| Receptor | GABA EC50 (n) | n | 10 mM ethanol | 30 mM ethanol | 100 mM ethanol | 300 mM ethanol |
| α6(R100Q)β3δ | 0.68 ± 0.1 (5) | 8 | 99.3 ± 15.0 | 180.1 + 28.2 | 275.3 ± 32.4 | 389.2 ± 65.0 |
| α6β3δ | 0.70 ± 0.4 (6) | 10 | 41.2 ± 4.3 | 92.5 ± 9.0 | 125.3 ± 20.5 | 245.0 ± 33.6 |
| α6(R100Q)β2δ | 0.51 ± 0.09 (5) | 7 | 0 | 24.5 ± 10.7 | 97.0 ± 11.2 | 199.0 ± 38.1 |
| α6β2δ | 0.50 ± 0.03 (5) | 6 | 0 | 23.1 ± 7.9 | 88.4 ± 15.6 | 175.0 ± 35.8 |
| α6(R100Q)β1δ | 0.62 + 0.04 | 8 | 0 | 24.1 ± 4.0 | 50.3 ± 7.8 | 185.2 ± 9.4 |
| α6β1δ | 0.56 + 0.07 | 9 | 0 | 21.2 ± 3.3 | 52.0 ± 5.6 | 167.9 ± 10.0 |
| α6(R100Q)β2/3γ2L/S | 19 ± 3.5 (6) | 16 | 0 | 0 | 40.3 ± 7.8 | 167.5 ± 14.2 |
| α6β2/3γ2L/S | 19 ± 0.5 (6) | 10 | 0 | 0 | 39.0 ± 7.5 | 182.6 ± 11.3 |
| α1β3δ | 0.56 ± 0.05 (4) | 8 | 32.5 ± 5.4 | 88.2 ± 7.0 | 117.5 ± 10.6 | 295.3 ± 19.7 |
| α1β2/3γ2L | 6.8 ± 0.8 (5) | 9 | 0 | 0 | 34.4 ± 9.9 | 147.3 ± 12.9 |
| α1β2/3γ2S | 8.8 ± 1.1 (6) | |||||
a
For each indicated subunit combination, GABA dose-response relationships were determined by fitting the Hill equation (see Methods). Current enhancement by ethanol was measured by co-application of ethanol and GABA (~EC30). Reported values are mean (±s.d.) percent increases above responses to GABA alone, zeroes represent measurements of no change in current, and n indicates the number of oocytes used to determine the average ethanol dose response curves. In cases where the identities of β or γ2 subunits did not lead to differences, results have been pooled.