Chronic sucrose ingestion enhances mu-opioid discriminative stimulus effects

David C. Jewett, Martha K. Grace, Allen S Levine

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Sucrose affects a variety of opioid-related behaviors. We hypothesized that, if sucrose ingestion alters opioidergic circuitry, opioid-induced discriminative stimulus effects would be enhanced following sucrose intake. In the present study, rats were trained to discriminate nalbuphine (3.2 mg/kg, s.c.) from saline in an operant choice procedure. After acquiring the discrimination, subjects were injected with a single nalbuphine dose (0.1-3.2 mg/kg) and given 30-min access to 30% sucrose or water. Sucrose consumption did not alter nalbuphine's discriminative stimulus effects under these conditions. During subsequent tests, training was suspended, and rats received continuous access to sucrose (9 days) or water (8 days). Chronic sucrose consumption increased the potency of nalbuphine to produce its discriminative stimulus effects by 3-fold. These findings suggest chronic sucrose consumption results in changes in opioid-system function that modulates the effects of exogenously administered opioids.

Original languageEnglish (US)
Pages (from-to)48-52
Number of pages5
JournalBrain Research
Issue number1-2
StatePublished - Jul 19 2005

Bibliographical note

Funding Information:
Research supported by USPHS grants DA 03999 and 01533, the Department of Veterans Affairs and the Minnesota Obesity Center.


  • Drug discrimination
  • Food intake
  • Nalbuphine
  • Sweet taste


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