Influence of chronic ethanol exposure on nitrous oxide analgesia in mice

The purpose of this study was to determine whether sensitivity to nitrous oxide analgesia was altered by chronic ethanol exposure. Control mice exposed to 25%, 50%, and 75% nitrous oxide in oxygen demonstrated a concentration-related analgesic effect, as measured by the acetic acid abdominal constriction test. Other mice previously exposed to ethanol vapors for 72 h exhibited a significantly reduced sensitivity to nitrous oxide analgesia. The dose-response curve of the chronic ethanol-exposed group was shifted to the right of that of the control mice. These findings suggest the possibility that subjects with a history of alcohol abuse might have reduced responsiveness to nitrous oxide in a clinical setting.