Effects of naloxone on cerebral I/R-induced SOD protein level. Immunoblot analysis was performed in sham operated (sham), vehicle (vehicle+I/R), and naloxone (0.03 mg, naloxone +I/R) infusion group with antibodies against Mn and Cu/Zn-SOD after 24 h reperfusion. The relative protein intensity was expressed as fold of the content to ipsilateral side of the sham group. Data were presented as mean+- SEM,