Nitrous oxide with fentanyl and droperidol minimizes lipid peroxidation in the liver

We have studied the level of lipid peroxidation in the liver of rats exposed to nitrous oxide plus oxygen or injected with droperidol of fentanyl. The effect of nitrous oxide used in combination with droperidol and fentanyl was also investigated. All the tested anaesthetics caused lipid peroxidation in the rat liver. It seems likely, however, that the mechanism by which droperidol and fentanyl initiate lipid peroxidation differs from that which nitrous oxide uses. Free radical products and/or activated oxygen species are produced during fentanyl and droperidol metabolism in the liver. However, nitrous oxide is not metabolized in the liver and probably undergoes one electron reduction outside the liver thus producing free radical products and/or activated oxygen species which are able to diffuse and initiate lipid peroxidation in the liver. It was also found that the level of lipid peroxidation in the liver of rats injected with droperidol and fentanyl and then exposed to nitrous oxide was low and close to that of the control animals. We suggest that, when used in combination, the products generated outside the liver as a result of nitrous oxide metabolism are transported to the liver and take part in reactions with the products of the metabolism of droperidol and fentanyl, thus decreasing the concentration of the species able to initiate lipid peroxidation.