D L Hymson

Nitrous oxide generalizes to a discriminative stimulus produced by ethylketocyclazocine but not morphine.

European journal of pharmacology October 1, 1984 M D Hynes, D L Hymson

Nitrous oxide, an analgesic and anesthetic gas, produces subjective effects in rats that resemble those of psychotomimetic drugs rather than morphine. Rats trained to discriminate ethylketocyclazocine, a psychotomimetic opioid, generalized the cue to nitrous oxide in a concentration-dependent manner, while rats trained to discriminate morphine did not generalize even at 80 percent nitrous oxide. The narcotic antagonist naltrexone did not block this generalization. These findings align with human studies and suggest that nitrous oxide, despite sharing some analgesic properties with morphine, has distinct subjective effects similar to psychotomimetic substances.