Fig. 4

Effects of opioid receptor (OR) antagonists on reactive oxygen species (ROS) products. This graph shows that selective OR antagonists reverse the attenuation of the ROS induced by hydromorphone (pre and per-condition). The ROS level was measured with using FACS (DCF-DA) in the cells treated only TBH (control group), and the cells treated with TBH, hydromorphone and/or one of selective delta, kappa, and mu opioid receptor antagonists, naltrindole, nor-binaltorphimine, and naloxone, respectively. The amount of ROS was expressed as Mean Fluorescence index.*<0.05 versus control group. ⁺<0.05 versus hydromorphone group