Superoxide dismutase activity in thymus cell suspension: effects of methionine-enkephalin and morphine

Superoxide dismutase activity of rat thymus-derived cells was studied by the inhibition of L-adrenaline auto-oxidation oxidation in vitro. The incubation of cells in the presence of methionine-enkephalin (Met-Enk) or morphine (2-20.10(-7) M and 2-8.10(-6) M, respectively) was performed in Krebs-bicarbonate buffer at 37 degrees C for 180 min. After a lag period of 30 to 60 min of incubation, both Met-Enk and morphine decreased the inhibitory activity of cell suspension on the adrenaline autooxidation. Naloxone blocked the effects of opioids in near equimolar concentrations. The observations suggest the interaction of opioids on superoxide anion production of T cell lymphocytes.