a, representative traces showing the reduction in holding current induced by the application of the α6/α4 antagonist furosemide, and the different sensitivity in +/+ and stg mice. b, scatter plot showing that furosemide reduces whole-cell conductance significantly more in +/+ mice than stg mice (+/+, −47 (interquartile range, −73, −36) pS/pF; stg, −19 (−37, 4) pS/pF; n = 9–13, p = 0.011, Mann Whitney test). c, zolpidem produces no significant change in whole-cell conductance in either stg or +/+ mice (+/+, 0.4 (−2, 2) %, n = 6, p = 0.8; stg, 0.7, (−3, 6) %, n = 6, p = 0.6, Wilcoxon matched pairs test).