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Figure 1. GABA-evoked responses at α1β3 and α1β3γ2 GABAA receptors.Xenopus laevis oocytes were injected with cRNA and subjected to two-electrode voltage-clamp electrophysiology as described in the methods. For experimentation, oocytes were clamped at −60 mV and full GABA concentration response relationships were obtained on each oocyte. (A) Representative GABA-evoked traces from oocytes injected with the denoted cRNA mixtures. Bars above each trace indicate application periods and GABA concentrations and “/” a wash period. Dotted lines indicate a 0 nA baseline and holding currents were −150 ± 93 nA, n = 6 for α1 + β3 (1:1) and −13 ± 10 nA, n = 9 for α1 + β3 (30:1). (B,C) Baseline subtracted peak current amplitudes for full GABA concentration-response curves at oocytes injected with the indicated cRNA mixtures using free subunits (B) or a concatenated β3-α1 construct (C) were fitted to the Hill equation using non-linear regression (fixed bottom of 0 and slope of 1) and normalized to the maximal fitted value (IGABA_max_fit). Averaged normalized data points are depicted as means ± S.E. as a function of the GABA concentration, fitted to the Hill equation and regression results are presented in Table 1. Each data point represents experiments from n = 5–9 oocytes from ≥2 batches. (D) α1β3 GABAA receptors can express in two stoichiometries of 2α1:3β3 (left) and 3α1:2β3 (right). The two binding sites for GABA at the β3(+)-α1(−) subunit interface are indicated by red arrowheads. Image published in: Che Has AT et al. (2016) Copyright © 2016, Macmillan Publishers Limited. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution license Larger Image Printer Friendly View

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