Covalent reaction at the functional level.

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.