Figure 5.

Effects of curine and guattegaumerine on the inhibition of rhodamine 123 efflux by verapamil. HTC-R cells were grown to confluence in DMEM and rhodamine accumulated for 90 min at 37 °C. After washing the cells, the efflux of rhodamine was initiated at 37 °C by the addition of PBS (control) or PBS containing verapamil, verapamil and curine, or verapamil and guattegaumerine at 100 μM each. For the time indicated in abscissa, the amount of rhodamine output from cells was measured by fluorescence. The results are expressed as a percentage of rhodamine 123 remaining in the cells. They are representative of at least two independent experiments and show the mean ± SD of triplicate plates.