Inhibition of Superoxide Production and Ca2+ Mobilization in Human Neutrophils by Halothane, Enflurane, and Isoflurane

The inhibitory effects of three inhalation anesthetics, i.e., halothane, enflurane, and isoflurane, on superoxide production and the intracellular mobilization of calcium in human neutrophils were studied. The superoxide production induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was inhibited by the anesthetics, but the binding of FML[3H]P to the cells and the superoxide-forming NADPH oxidase of the phagocytic vesicles were not inhibited. The inhibition of the cellular superoxide production was partially reversed by the addition of a calcium ionophore, A23187. The increase in intracellular free calcium monitored by a calcium-sensitive fluorescent probe, quin-2 and the release of calcium from hydrophobic environment monitored by chlortetracycline were inhibited dose dependently by the anesthetics. These observations suggest that decreased mobilization of intracellular Ca2+ is one of the mechanisms by which the anesthetics inhibited the superoxide production of human neutrophils stimulated by FMLP.