Fig. 3. Transepithelial transport of [³H]-digoxin (5 μm) across a Caco-2 cell culture monolayer in the absence (control, A ) or presence of various opioids (20 μm, B –H ). Translocation from basal to apical compartments is indicated by triangles and solid line; translocation from apical to basal compartments is indicated by the squares and dotted line. Data are mean ± SD from three or more experiments.