Morphine inhibited respiratory burst of neutrophils and scavenged oxygen free radicals.

AIM

To study the effects of morphine on active oxygen free radicals.

METHOD

Chemiluminescence method was used to measure (a) active oxygen generation induced by respiratory burst of neutrophils from human blood stimulated with phorbol myristate acetate (PMA), (b) Superoxide anion (O2.-) induced by xanthine-xanthine oxidase system, (c) hydroxyl radical (.OH) generated by ascorbic acid (AA)-Cu(2+)-zymosan, and (d) the release of H2O2.

RESULTS

The (a), (b), (c), and (d) were scavenged by morphine and their median inhibitory concentrations (IC50 and 95% confidence limits) were 21.1 (13.0-34.0), 54.1 (50.0-58.5), 224.0 (128.2-390.8), and 66.9 (62.9-71.0), nmol L-1, respectively.

CONCLUSION

The immunosuppressant effect of morphine was related to its free radicals scavenging action.