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Abused Inhalants and Central Reward Pathways
Author(s) -
RIEGEL ARTHUR C.,
FRENCH EDWARD D.
Publication year - 2002
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2002.tb04170.x
Subject(s) - ventral tegmental area , nucleus accumbens , dopamine , mesolimbic pathway , chemistry , neuroscience , pharmacology , dopaminergic , brain stimulation reward , psychology , medicine
A bstract : Inhalant abuse remains a significant health problem among the younger segment of society. In fact, the use of inhalants in this population trails only that of nicotine, alcohol, and marijuana. Toluene is a common ingredient in many of the substances sought out for inhalation abuse, apparently for its euphorigenic and hallucinogenic effects. Because drugs of abuse share the common property of altering the activity of mesolimbic dopamine neurons, it is reasonable to suspect that toluene‐induced changes in this CNS pathway may underlie its abuse potential. Here we will provide in vivo and in vitro electrophysiological data and behavioral evidence linking toluene exposure in rats to activation of mesolimbic dopamine neurons. Exposure of rats to 11,000 ppm of inhaled toluene produced time‐dependent activation of dopamine neurons within the midbrain ventral tegmental area (VTA). In the rat brain slice preparation, perfusion with toluene (23‐822 μM) also evoked an increase in activity of both dopamine and nondopamine neurons within the VTA. These excitatory effects could not be found in adjacent non‐VTA nuclei, nor were they sensitive to the glutamate antagonists CGS19755 or CNQX. In behavioral studies, systemic administration of toluene produced a dose‐dependent locomotor hyperactivity that was attenuated by either pretreatment with the D2 dopamine receptor antagonist remoxipride or by 6‐hydroxydopamine lesions of the nucleus accumbens. These findings show that toluene can activate dopamine neurons within the mesolimbic reward pathway, an effect that may underlie the abuse potential of inhaled substances containing toluene.