Figure 6. Inhibition by TBPS or picrotoxin of GABA-evoked currents mediated by α1(K278M)β2γ2 receptors.

A, top traces, time-dependent inhibition of episodic GABA (100 μm for 100 ms) evoked currents by TBPS (10 μm) or, bottom traces, picrotoxin (100 μm) recorded every 60 s. The time required to reach maximal inhibition in the presence of episodic GABA was used to determine the duration of bath application of TBPS or picrotoxin in the absence of GABA. B, block after exposure to TBPS and picrotoxin in the absence of episodic GABA. C, Graph of % inhibition by TBPS or picrotoxin with or without episodic GABA application. Data from mutant receptors are shown in the filled bars. Open bars are wild-type data reproduced from Fig. 2C. Data are represented as means ± SEM (n≥ 5). Use-independent blockade of α1(K278M)β2γ2 receptors by picrotoxin was significantly lower than that of α1β2γ2 receptors (*P < 0.01, one-way ANOVA with post hoc Tukey's test).