Percent mortalities of zebrafish embryos after 1 to 48 hpf exposures to toxic compounds in the presence or absence of ABC transporter inhibitors. The graphs show mortalities caused by different concentrations of vinblastine without and with 5 μM CsA (A) or 5 μM PSC833 (B) and of phenanthrene (C) and of vincristine (D) without and with 5 μM CsA. Depicted are mean values and standard deviations of independent replicates. For vinblastine and phenanthrene concentration-response regressions were determined using the logistic HILL model with bottom restrained to 0 and top restrained to 100. The dotted lines indicate the concentration causing mortality in 50% of the embryos (LC50). Refer to Additional file 1: Table S3 for details on the number of independent replicates, LC50 values with confidence intervals and further curve parameters. Statistically significant differences in mortalities between treatments without and with inhibitors at respective vinblastine, vincristine or phenanthrene concentrations were determined with the paired (vinblastine, vincristine) or the regular t-test (phenanthrene) and are indicated by asterisks (P <0.05).