Figure 4. Concentration inhibition curves for rat and Drosophila GABA_A receptors.

A, Concentration inhibition curve for α₁β₂γ₂ and α₁β₂δ GABA_A receptors. Increasing concentrations of PCCP⁻ were applied together with GABA EC₁₀. Individual inhibition curves were standardized and subsequently averaged (Mean ± SD, n = 4). Data are compared with those obtained from α₁β₂γ₂ receptors. Inhibition of the wild type and mutant RDL Drosophila GABA_A receptor by PCCP⁻ and Picrotoxin. Concentration inhibition curves of (B) PCCP⁻ and, (C) picrotoxin were determined in wild type (circles) and mutant (squares) receptors. Currents were activated with a concentration of GABA eliciting 10% of the maximal current amplitude (EC₁₀) and inhibited with increasing concentration of PCCP⁻ or picrotoxin. Individual curves were standardized to initial current amplitudes and subsequently averaged. Data are shown as mean ± SD (n = 3).