title: Nitrous oxide "analgesia": resemblance to opiate action.
abstract: 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.
mesh_terms: D000698:Analgesia; D000818:Animals; D004361:Drug Tolerance; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000494:pharmacology; D009609:Nitrous Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D009270:Naloxone; D009271:Naltrexone; D009020:Morphine; D009609:Nitrous Oxide