Blockade of the discriminative stimulus effects of ethanol with 5-HT3 receptor antagonists

Kathleen A. Grant, James E. Barrett

Research output: Contribution to journalArticlepeer-review

96 Scopus citations

Abstract

The ability of selective 5-HT3 receptor antagonists to block the discriminative stimulus effects of ethanol was investigated in pigeons trained with food reinforcement to discriminate ethanol (1.5 g/kg; IG) from water. The 5-HT3 receptor antagonists that are substituted tropines, ICS 205-930 (0.1-0.56 mg/kg) and MDL 72222 (3.0-17.0 mg/kg), blocked ethanol-appropriate responding, in a dose-dependent manner, suggesting that some of the discriminative stimulus effects of ethanol are mediated via the 5-HT3 receptor. The blockade the discriminative stimulus effects of ethanol occurred in the presence of approximately 25-40 mM blood ethanol levels. Furthermore, the ethanol dose-effect function was shifted to the right by increasing doses of MDL 72222, suggesting a surmountable antagonism of the discriminative stimulus effects of ethanol. However, the benzamide zacopride (0.56-1.7 mg/kg), which is also a 5-HT3 receptor antagonist, did not block the discriminative stimulus effects of ethanol. In addition, the dopaminergic antagonist haloperidol and the 5-HT2 receptor antagonist ketanserin also failed to block the ethanol discrimination. The results suggest that 5-HT3 mediated neurotransmission is an important component of ethanol's discriminative stimulus effects, but that the structural characteristics of the selective 5-HT3 receptor antagonists influence their ability to block this action of ethanol. Furthermore, these findings implicate a significant role of 5-HT3 activity in the behavioral effects of ethanol that may provide a pharmacological means for therapeutic intervention of alcohol abuse.

Original languageEnglish (US)
Pages (from-to)451-456
Number of pages6
JournalPsychopharmacology
Volume104
Issue number4
DOIs
StatePublished - Aug 1 1991
Externally publishedYes

Keywords

  • 5-HT
  • Drug -discrimination
  • Ethanol
  • Ethanol antagonist
  • Serotonin antagonists
  • Serotonin receptors

ASJC Scopus subject areas

  • Pharmacology

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