Table 2. Covalent reaction at the functional level.
| Mutated receptor | Mutation homolo-gous to | DZ | n | 3-NCS | p | 3-NCS +DZ | n |
| α1S204Cβ2γ2 + | 126±9 | 3 | 4±4 | n.s. | 115±34 | 3 | |
| α1S205Cβ2γ2 | 113±7 | 3 | 60±43 | <0.03 | 131±32 | 3 | |
| α1T206Cβ2γ2 | 82±18 | 6 | 119±51 | <0.01 | 204±62 | 4 | |
| α2S204Cβ2γ2 + | α1S204C | 215±42 | 3 | 1±10 | n.s. | 218±30 | 3 |
| α2S205Cβ2γ2 | α1S205C | 191±53 | 3 | 35±10 | <0.01 | 177±25 | 3 |
| α2T206Cβ2γ2 | α1S206C | 148±8 | 3 | 53±29 | <0.01 | 168±54 | 3 |
| α3S229Cβ2γ2 | α1S204C | l.e. | l.e. | l.e. | |||
| α3S230Cβ2γ2 | α1S205C | 149±44 | 3 | 15±11 | n.s. | 158±44 | 3 |
| α3T231Cβ2γ2 | α1S206C | 88±45 | 3 | 28±16 | <0.03 | 165±8 | 3 |
| α5T208Cβ2γ2 | α1S204C | 129±38 | 7 | 23±18 | <0.05 | 83±25 | 5 |
| α5S209Cβ2γ2 | α1S205C | 103±3 | 3 | 46±17 | <0.01 | 140±20 | 3 |
| α5T210Cβ2γ2 | α1S206C | 82±14 | 3 | 10±5 | n.s. | 47±8 | 3 |
| α6S203Cβ2γ2 + | α1S204C | 50±20* | 3 | 0±2 | n.s. | 57±21* | 3 |
| α6N204Cβ2γ2 + | α1S205C | 70±40* | 3 | −4±6 | n.s. | 71±40* | 3 |
| α6T205Cβ2γ2 | α1S206C | 48±6* | 3 | 14±8 | <0.05 | 58±21* | 3 |
Mutated GABAA receptors were expressed in Xenopus oocytes. Allosteric stimulation by 1 µM diazepam was determined (column labelled DZ (diazepam)) at EC2–5 for GABA. Data are given as % allosteric modulation. In independent experiments oocytes were exposed to GABA followed by 10 µM 3-NCS and after removing non-covalently reacted 3-NCS, allosteric stimulation was determined (column labelled 3-NCS). Subsequently the same oocyte was exposed to 1 µM diazepam (column labelled 3-NCS + diazepam) and allosteric stimulation was determined as compared to the initial application of GABA. *1µM Abecarnil was used. l.e. low expression, expressed currents were too small for measurement of covalent effects. p was determined with the one-way ANOVA followed by a post-hoc Dunnett’s test where the non-responsive receptors indicated with (+) served as one of the samples (mean ± mean SD, 0.25±5.5, n = 4). Data are given as mean ±SD.