Effects of daily morphine administration and deprivation on choice and demand for remifentanil and cocaine in rhesus monkeys

Tammy Wade-Galuska, Chad M. Galuska, Gail Winger

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Choice procedures have indicated that the relative reinforcing effectiveness of opioid drugs increases during opioid withdrawal. The demand curve, an absolute measure of reinforcer value, has not been applied to this question. The present study assessed whether mild morphine withdrawal would increase demand for or choice of remifentanil or cocaine. Four rhesus monkeys chose between remifentanil and cocaine during daily sessions. Demand curves for both drugs were subsequently obtained. The effects of daily injections of 3.2 mg/kg morphine on both choice and demand for these drugs was assayed 3 and 20.5 hr after each morphine injection, and then during a postmorphine period. Three hours following morphine injections, choice of remifentanil over cocaine decreased and demand for remifentanil-but not cocaine-became more elastic. During morphine withdrawal (20.5 hr postinjection), choice of remifentanil increased and remifentanil demand became more inelastic in 3 of 4 monkeys. Cocaine demand also became more inelastic during this period. Four to five weeks following the morphine regimen, demand for both drugs was more inelastic relative to the initial determination. The results suggest that both the relative and absolute reinforcing effectiveness of remifentanil decreased following morphine administration and increased during morphine withdrawal. The absolute reinforcing effectiveness of cocaine also increased during morphine withdrawal. In addition, extended exposure to drug self-administration and/or exposure to the morphine regimen produced long-term increases in demand for both drugs.

Original languageEnglish (US)
Pages (from-to)75-89
Number of pages15
JournalJournal of the experimental analysis of behavior
Issue number1
StatePublished - Jan 2011
Externally publishedYes


  • Behavioral economics
  • Choice
  • Cocaine
  • Drug self-administration
  • Lever press
  • Remifentanil
  • Rhesus monkeys

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience


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