Drug and alcohol dependence
November 25, 1997
J P Zacny, A M Cho, A Y Toledano et al.
Being told what drug and effects to expect can change how people respond to nitrous oxide. Healthy volunteers could choose between inhaling nitrous oxide (10-40% concentration) or placebo (oxygen) after sampling both. One group was told the concentration and typical effects (tingling, euphoria, dysphoria); the other was only told the drug came from one of six classes. Thirty percent nitrous oxide was chosen more often than chance only by informed participants, and the probability of choosing 20-40% nitrous oxide was higher in the informed group. Subjective effects were unaffected, but psychomotor impairment at the highest concentration was greater in the non-informed group, suggesting that information can modulate reinforcing and impairing effects.
Anesthesiology
November 1, 1997
J L Galinkin, D Janiszewski, C J Young et al.
Sevoflurane, a volatile general anesthetic, and nitrous oxide, a gaseous anesthetic, produce different subjective, psychomotor, and analgesic effects at equal subanesthetic concentrations. In 12 healthy volunteers, sevoflurane caused greater amnesia, psychomotor impairment, and drowsiness than nitrous oxide, while only nitrous oxide provided analgesic effects. Recovery from both drugs was rapid. The distinct effect profiles align with their chemical and mechanistic differences.
Drug and alcohol dependence
November 1, 1996
J P Zacny, J M Klafta, D W Coalson et al.
Brief exposures (about 1.5 minutes) to nitrous oxide at concentrations of 20-80% in oxygen did not function as reinforcers in 11 healthy volunteers with modest lifetime psychoactive drug use. In a choice procedure, subjects sampled each concentration and placebo oxygen, then chose between them. 20%, 40%, 60%, and 80% nitrous oxide were chosen by five, four, three, and three subjects respectively, none exceeding chance levels. All concentrations produced psychoactive effects, with concentration-related subjective effects. The authors conclude that nitrous oxide inhaled in a manner similar to recreational use does not act as a reinforcer across a wide range of concentrations in this population.
Pharmacology, biochemistry, and behavior
June 1, 1996
S Yajnik, J P Zacny, C J Young et al.
A crossover, double-blind trial with eleven healthy volunteers tested whether acute drug tolerance develops to the subjective, cognitive, and psychomotor effects of subanesthetic nitrous oxide at doses of 0, 10, 20, 30, and 40%. Over a 120-minute inhalation period, there was little evidence of acute tolerance to the subjective or impairing effects at any concentration.
Neuroscience letters
May 10, 1996
J P Zacny, A M Cho, D W Coalson et al.
Inhaling nitrous oxide at increasing doses (10–40%) reduces pain intensity and the bother of pain from cold-water immersion, but this analgesic effect weakens over a 120-minute inhalation period (acute tolerance). Some pleasant subjective effects, such as elation and drug liking, also show acute tolerance. Other subjective effects and psychomotor impairment do not change significantly during the inhalation period, indicating no acute tolerance for those measures. The differing patterns of tolerance suggest that distinct neurochemical systems may mediate different effects of nitrous oxide.