title: The similarity of the action of nitrous oxide and morphine.
mesh_terms: D006801:Humans; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010146:Pain / Q000188:drug therapy
chemical_list: D009020:Morphine; D009609:Nitrous Oxide