Naloxone inhibits superoxide release from human neutrophils.
Using the superoxide dismutase inhibitable reduction of cytochrome c assay, we studied, the effect of (-) naloxone on N-formyl-methionyl-leucyl-phenylalanine (FMLP) stimulated superoxide (O2-) release from human neutrophils. Neutrophils were pre-incubated with the range of concentrations of (-) naloxone that is administered in models of experimental sepsis (10(-6) - 10(-4.5) M). (-) Naloxone inhibited O2- release in a dose dependent manner. 02- produced by a cell-free xanthine-xanthine oxidase system was not inhibited by (-) naloxone, indicating that (-) naloxone was not scavanging O2-. There was no difference between the effect of (-) and (+) naloxone suggesting that the inhibition of O2- was not specific for an opiate receptor. Another opiate antagonist, nalorphine, as well as the opiate agonist, morphine, also inhibited O2- release in the same concentration range. There was no difference between the effect of naloxone and morphine.
D004305:Dose-Response Relationship, Drug; D006801:Humans; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D009270:Naloxone; D009020:Morphine