Dose–response curves for selected quinoline derivatives. A Five dpf zebrafish pretreated with cinchonidine at variable doses for 1 h, followed by treatment with 200 μM neomycin demonstrate significant dose-dependent protection (F(4, 45) = 91.46, p < 0.0001, one-way ANOVA). B Cinchonidine-induced hair cell protection is maintained at higher doses of neomycin (200 and 400 μM). C Zebrafish pretreated with variable doses of quinine for 1 h, followed by treatment with 200 μM neomycin demonstrate significant dose-dependent protection (F(4, 45) = 41.34, p < 0.0001, one-way ANOVA). D Quinine-induced hair cell protection is maintained at higher doses of neomycin (200 and 400 μM). E Zebrafish pretreated with tacrine for 1 h, followed by treatment with 200 μM neomycin demonstrate significant dose-dependent protection (F(4, 45) = 74.83, p < 0.0001, one-way ANOVA). F Tacrine-induced hair cell protection is maintained at higher doses of neomycin (200 and 400 μM). For all graphs, data points represent the mean hair cell survival of eight to ten fish. Error bars = ±1 SD from the mean. Data for these three drugs as well as the remaining five quinoline derivatives are presented in Tables 1 and 2.