Controlled and behaviorally relevant levels of oral ethanol intake in rhesus macaques using a flavorant-fade procedure

Simon N. Katner, Claudia T. Flynn, Stefani N. Von Huben, Amber J. Kirsten, Sophia A. Davis, Christopher C. Lay, Maury Cole, Amanda J. Roberts, Howard S. Fox, Michael A. Taffe

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Background: Flavorant-fading procedures can initiate and maintain oral ethanol intake in rodents. The present study developed a similar procedure to achieve controlled and behaviorally relevant levels of ethanol intake in monkeys. Methods: Male rhesus macaques (N = 13) were initially given the opportunity to consume 0.5 g/kg of a 1% (w/v) ethanol plus 4% (w/v) Tang solution in 1-hr limited-access sessions without the requirement of an operant response. Once consumption was stable at a particular concentration (%) and/or amount (g/kg), animals were given access to higher concentrations and/or amounts of ethanol. Animals were tested on a bimanual motor skill (BMS) task 20 and 90 min after consumption to assess behavioral impairment. Blood alcohol levels (BALS) were assessed after a session in which animals had the opportunity to consume up to 3.0 g/kg of 6% (w/v) ethanol. Results: The gradual fading up of higher concentrations and amounts of ethanol resulted in controlled and robust levels (>2.0 g/kg) of ethanol intake in half of the subjects. Increasing the concentration of the sweetener from 4 to 6% (w/v) was effective in initiating consumption in three animals. Two monkeys required the additional step of presenting the increased-sweetener solutions after a meal (postprandial consumption) to initiate significant ethanol intake. Animals were significantly impaired on the BMS task after consumption of 2.0, 2.5, and 3.0 g/kg of ethanol. Individual consumption ranging from 0.8 to 3.0 g/kg of ethanol produced BALs of 18 to 269 mg/dl. Conclusions: The flavorant-fading procedure was effective in producing behaviorally relevant levels of ethanol consumption in rhesus macaques. This model facilitated a randomized-dose procedure to determine the behavioral effects of 0.5 to 3.0 g/kg of ethanol. This procedure therefore is of significant utility in determining behavioral or physiologic effects of specific doses of consumed ethanol in monkeys.

Original languageEnglish (US)
Pages (from-to)873-883
Number of pages11
JournalAlcoholism: Clinical and Experimental Research
Issue number6
StatePublished - Jun 2004
Externally publishedYes


  • Alcohol
  • Ethanol
  • Nonhuman primate
  • Rhesus macaque
  • Self-administration

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Toxicology
  • Psychiatry and Mental health


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