The βN265M mutation reduces the channel gating effects of a α1M236W mutation that mimics etomidate.

Panel A) Data are reproduced from Guitchounts et al [38] showing mean ± SD GABA concentration-response, normalized to maximal currents, from oocytes expressing concatenated receptor dimer and trimer constructs. Lines through data points represent non-linear least squares logistic fits (Eq. 1, methods). Solid squares represent β2-α1/γ2L-β2-α1 receptors (GABA EC50 = 36 µM) and open circles represent β2-α1M236W/γ2L-β2-α1M236W receptors (EC50 = 1.0 µM). Panel B) Data points are mean ± SD current responses to GABA, normalized to maximal currents. Solid diamonds represent β2N265M-α1/γ2L-β2N265M-α1 receptors (GABA EC50 = 76 µM; 95% CI = 63 to 92 µM) and open triangles represent β2N265M-α1M236W/γ2L-β2N265M-α1M236W- receptors (EC50 = 25 µM; 95% CI = 22 to 29 µM).