Naphthalene–etomidate modulation of α₁β₃γ_2L γ-aminobutyric acid type A (GABA_A) receptor currents: simultaneous addition protocol. (A) Representative current traces obtained upon application of γ-aminobutyric acid (GABA) at a concentration that evokes 50% of the current evoked by 1 mM GABA (EC₅₀ GABA). The first and last traces were controls obtained in the absence of naphthalene–etomidate, and the middle trace was obtained with simultaneous addition of 300 μM naphthalene–etomidate along with GABA. (B−E) Representative current traces obtained upon application of GABA at a concentration that evokes 5% of the current evoked by 1 mM GABA (EC₅ GABA) along with the indicated positive allosteric modulator. In each panel, the first and last traces were controls obtained in the absence of naphthalene–etomidate, and the middle trace was obtained with simultaneous addition of 300 μM naphthalene–etomidate along with GABA + modulator. In each panel, the dashed line shows the average control peak current produced in the absence of naphthalene–etomidate. (F) Percent change in peak current amplitude produced by 300 μM naphthalene–etomidate. Positive values indicate that naphthalene–etomidate enhanced peak currents, whereas negative values indicate that it reduced peak currents. Each symbol represents data from a single oocyte experiment (n = 6 oocyte experiments/drug). Means ± SD are indicated for each data set. Statistically significant change in current amplitude was produced by naphthalene–etomidate. **P < 0.01; ***P < 0.001; ****P < 0.0001.