Fig. 3

Maximal ACh-induced current and labeling of Epipedobates anthonyi α4β2 nAChRs. Maximal ACh-induced currents were measured at 4 (A, n = 14–18 oocytes) and at 7 (B, n = 21) days after injection. The presence of cysteine in location 108, either combined with F106 [β2(FC), green] or with L106 [β2(LC), wild type, orange], decreases the magnitude of ACh-stimulated maximal currents through the α4β2 receptors, compared with β2(FS) (gray) and β2(LS) (violet). The bold font indicates a substitution introduced in the wild-type receptor. Following recordings shown in B, oocytes were treated with the radiolabeled antibody.¹²⁵I-mAb 295 to quantify the specific binding, i.e., the number of β2-containing nAChRs expressed in the plasma membrane (C, n = 3, 7 pooled oocytes each experiment). Cpm stands for counts per minute. α4:β2 RNA injection ratios favoring HS (1:7) and LS (7:1) stoichiometries are indicated on the X-axis. Data are presented as means ± SD and were analyzed using two-way ANOVA, followed by pairwise comparisons corrected for multiple comparisons with Holm-Šídák’s test. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001