Discriminative Stimulus Effects of Abused Inhalants

Abstract

Inhalants are a loosely organized category of abused compounds defined entirely by their common route of administration. Inhalants include volatile solvents, fuels, volatile anesthetics, gasses, and liquefied refrigerants, among others. They are ubiquitous in modern society as ingredients in a wide variety of household, commercial, and medical products. Persons of all ages abuse inhalants but the highest prevalence of abuse is in younger adolescents. Although inhalants have been shown to act upon a host of neurotransmitter receptors, the stimulus effects of the few inhalants which have been trained or tested in drug discrimination procedures suggest that their discriminative stimulus properties are mediated by a few key neurotransmitter receptor systems. Abused volatile solvent inhalants have stimulus effects that are similar to a select group of GABA positive modulators comprised of benzodiazepines and barbiturates. In contrast the stimulus effects of nitrous oxide gas appear to be at least partially mediated by uncompetitive antagonism of NMDA receptors. Finally, volatile anesthetic inhalants have stimulus effects in common with both GABA positive modulators as well as competitive NMDA antagonists. In addition to a review of the pharmacology underlying the stimulus effects of inhalants, the chapter also discusses the scientific value of utilizing drug discrimination as a means of functionally grouping inhalants according to their abuse-related pharmacological properties.

Assessment of Abuse-Related Discriminative Stimulus Effects of Nicotine Aerosol in Rodents

“…The ability of inhaled drugs to fully substitute for an injected drug training stimulus has been repeatedly demonstrated for abused inhalant vapors, volatile anesthetic vapors and anesthetic gasses (for review see Shelton, 2018). It is therefore interesting that a recent study (Lefever et al, 2019) reported that inhaled nicotine aerosol only engendered partial substitution (46-49%) for an injected nicotine training condition in mice.…”

Sexual behaviour is impaired by the abused inhalant toluene in adolescent male rats

“…Many drugs of abuse, in particular central nervous system (CNS) depressant drugs, impair sexual behaviour (Frohmader, Pitchers, Balfour, & Coolen, 2010;Pfaus et al, 2010). Several inhalants, mainly organic solvents, are CNS depressant drugs (Balster, 1998;Shelton, 2016), but their effect on sexual behaviour has not been studied.…”