Fig. 5. Formation of reactive oxygen species (ROS) in the cultured human umbilical vein endothelial cells after exposure to different concentrations of morphine (10−10to 10−4m). Intracellular levels of ROS were measured by dihydroethidium under flow cytometry. *P < 0.05 in comparison with controls. +P < 0.05 in comparison with 10−10m morphine. Relative densities of ROS were analyzed by analysis of variance and are shown as mean ± SEM. n = 3 or 4 independent experiments in triplicate.
