Fig. 13. Effects of p-glycoprotein (P-gp) inhibitors on transepithelial flux of daunorubicin (A–F) or rhodamine 123 (G,H) across Drosophila tubules set up in Ramsay assays. Each panel shows the flux (mean + S.E.M.) for control tubules (filled bars) exposed to the dye alone at the indicated concentration (µmol l^–1) and those treated with the same dye concentration and a P-gp inhibitor at the concentration (µmol l^–1) indicated (open bars). Abbreviations: daunorubicin (DNR), verapamil (VRP), quinacrine (QUIN), rhodamine 123 (R123); tetraethylammonium (TEA). Significant differences (P<0.05) between control and experimental groups indicated by asterisks. N=7–10 tubules for each bar.