Discriminative stimulus effects of nitrous oxide in mice: comparison with volatile hydrocarbons and vapor anesthetics.
Behavioural pharmacology February 1, 2014 Kellianne J Richardson, Keith L Shelton
Nitrous oxide (N₂O) gas produces abuse-related behavioral effects that may differ from other inhalants. In a drug discrimination experiment, 16 mice were trained to distinguish between 10-minute exposure to 60% N₂O mixed with oxygen and pure oxygen. Mice learned this discrimination in 40 days. N₂O itself fully substituted for the training condition in a concentration-dependent manner, with full substitution requiring 7 minutes of exposure. The aromatic hydrocarbon toluene almost fully substituted for N₂O, while other compounds like 1,1,1-trichloroethane, methoxyflurane, isoflurane, and ethanol showed lesser substitution. D-amphetamine and the odorant 2-butanol did not substitute. The varying degrees of incomplete substitution suggest that N₂O's discriminative stimulus properties—and likely its subjective effects in humans—are probably not unique, though its overall effects may include novel components.