Nitrous oxide "analgesia": resemblance to opiate action

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Science  26 Nov 1976:
Vol. 194, Issue 4268, pp. 967-968
DOI: 10.1126/science.982058


Nitrous oxide produced a dose-related "analgesia" in mice (median effective dose, 55 percent). The analgesia was evaluated by means of a phenylquinone writhing test. Narcotic antagonists or chronic morphinization reduced nitrous oxide analgesia. Either nitrous oxide releases an endogenous analgesic or narcotic antagonists have analgesic antagonist properties heretofore unappreciated.