Send to

Choose Destination
See comment in PubMed Commons below
Psychopharmacology (Berl). 1996 Jul;126(2):110-4.

Naloxone effects on sucrose-motivated behavior.

Author information

  • 1Department of Psychology, University of Minnesota, Minneapolis 55455, USA.


The opioid system plays an important role in feeding. In general, opioid agonists typically increase feeding and opioid antagonists decrease feeding in non-food restricted animals. In food restricted animals the effects of these drugs are substantially reduced. Opioid antagonists have shown a marked effectiveness at reducing consumption of sweet foods. Explanations for this robust effect have typically focused on drug induced changes in taste, taste perception, or palatability. The current study relates the effects of the opioid antagonist naloxone on motivation to obtain different sucrose concentrations to the drug's effects on unrestricted sucrose solution consumption. Changes in motivation to respond were assessed under a progressive ratio reinforcement schedule (PR) which required increased response cost for each successive unit of sucrose solution. Motivation, as measured by the PR, increased as sucrose concentration increased and naloxone produced a dose-dependent decrease in motivation to respond for a given sucrose concentration. Thus, the effectiveness of naloxone was indirectly related to strength of the sucrose concentration. Under unrestricted access to sucrose solutions, naloxone reduced consumption greatest under the higher concentrations. The data suggest at least part of naloxone's effects on sweet tasting food may be mediated through endogenous opioid reward systems that are reflected in measures of motivation.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Loading ...
    Support Center