title: Bitonic dose-response functions for reinforcing and self-reported effects of nitrous oxide in humans.
abstract: The reinforcing and self-reported effects of nitrous oxide (10%, 30%, and 50% N(2)O in O(2)) were examined in 13 humans. During each of three sessions, subjects sampled one dose of N(2)O and 100% O(2) (placebo) for 10 min each, separated by 30-min recovery periods. The agents were identified by letter code, and later in the session, subjects chose nine times, once every 5 min, among N(2)O (e.g., "Agent A"), placebo (e.g., "Agent B"), or "neither" (also 100% O(2), identified as "drug-free air"). Self-reported and psychomotor effects were measured at various times. Dose-response functions varied across subjects and included bitonic, monotonic increasing, monotonic decreasing, U-shaped, and flat dose-response functions for reinforcing and/or self-reported effects. For subjects who showed bitonic reinforcing effects, the descending limb of the dose-response function could not be attributed to behavioral impairment. This study replicates previous studies showing dose-dependent effects of N(2)O, as well as between-subject variability in N(2)O effects. Bitonic dose-response functions for some subjects extend the generality of the phenomenon of bitonicity of drug effects to N(2)O effects in humans.
authors.affiliation: Department of Anesthesia and Critical Care, The University of Chicago, 5841 South Maryland Avenue, MC 4028, Chicago, IL 60637, USA. dwalker@airway.uchicago.edu
authors.forename: Diana J
authors.initials: DJ
authors.lastname: Walker
authors.forename: James P
authors.initials: JP
authors.lastname: Zacny
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects* / Q000502:physiology; D000704:Analysis of Variance; D002755:Choice Behavior / Q000187:drug effects* / Q000502:physiology; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D009609:Nitrous Oxide / Q000008:administration & dosage*; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D012054:Reinforcement, Psychology
chemical_list: D009609:Nitrous Oxide