Morphine-based secondary reinforcement: Effects of different doses of naloxone

Richard Marcus, Gilbert Carnathan, Roger Meyer, Joseph Cochin

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The effects of different doses of naloxone on morphine-based secondary reinforcement were studied in rats. On the first day a neutral stimulus (buzzer) was repeatedly paired with intravenous morphine infusions. Drug treatments consisted of Low, Medium, or High Naloxone doses, or No Naloxone. The next day the ability of the buzzer and saline infusion to support lever pressing was tested. High Naloxone blocked, and Low Naloxone partially blocked this morphine-based secondary reinforcement. Subjects in the Medium Naloxone group demonstrated an apparent avoidance of the lever, suggesting that the morphine infusions were aversive at this dosage level of naloxone. The secondary reinforcement tests reliably predicted behavior on a subsequent test for acquisition of morphine-seeking behavior.

Original languageEnglish (US)
Pages (from-to)247-250
Number of pages4
Issue number3
StatePublished - Jan 1 1976

All Science Journal Classification (ASJC) codes

  • Pharmacology


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