Fig 2. Subunit combinations with detectable function but were not activated by 2’MeO6MF.

(A) Representative traces illustrating the robust response elicited by 3 mM GABA, and the lack of activity of 100 μM Zn²⁺ and 100 μM 2’MeO6MF at α2β3 (20:1) GABA_ARs (n = 6). (B) The injection of γ2L mRNA at high amounts (28–35 ng/oocyte) resulted in constitutively active channels which were inhibited by 100 μM Zn²⁺, but were not sensitive to 60 mM GABA, 100 μM etomidate and 100 μM 2’MeO6MF (n = 5). (C) The injection of β3 mRNA (5 ng/oocyte) resulted in the formation of functional receptors. Representative traces of β3 homomeric receptors responses to 1–60 mM GABA (top;), 3–300 μM of 2’MeO6MF and 100 μM Zn²⁺ (bottom). (D) 2’MeO6MF concentration-response curve for β3 homomeric receptors (n = 5). The efficacy of 2’MeO6MF as an inverse agonist is expressed as a fraction of the inhibited spontaneous current (I) normalised against the holding current (I _holding). Data are presented as mean ± SEM. Bars indicate durations of drug application. The holding current values are represented by the dotted lines.