Figure 6.

α7 2Y-A mutant nAChRs exhibit larger ACh-evoked currents compared with wild-type α7. Xenopus oocytes expressing wild-type or α7 2Y-A (Y386A, Y442A) receptor were recorded using two-electrode voltage clamp. a, ACh-evoked currents for wild-type and mutant α7 nAChRs. Increasing ACh concentrations are indicated and expressed in micromolar. b, ACh dose-response curves for wild-type α7 (squares, dashed line; n = 63) and mutant α7 2Y-A receptors (triangle, solid line; n = 34). Currents were evoked by successive test pulses (3 s) with increasing ACh concentrations, applied every 90 s. Lines through the data points correspond to the best fit with a Hill equation (supplemental Table 1, available at www.jneurosci.org as supplemental material). c, Maximal recorded currents (I_max) were plotted as a function of the drug applied at wild-type α7 (open bars) or α7 2Y-A mutant receptor (gray bars). Genistein (gen) and genistin (igen) concentrations were 10 μm. The numbers in parentheses indicate the number of cells tested in each condition. Data are expressed as mean ± SEM and show that ACh-evoked currents are higher for α7 2Y-A nAChRs and that these receptors are insensitive to genistein and pervanadate (perv) treatment. Significant differences were calculated by unpaired, two-tailed Student's t tests (^*p < 0.01; ★p < 0.001).