5 years ago

Naloxone effects on extinction of ethanol- and cocaine-induced conditioned place preference in mice

Christopher L. Cunningham, Christa A. Houck, Laura Font



Previous studies found that naloxone (NLX) facilitated choice extinction of ethanol conditioned place preference (CPP) using long (60 min) test sessions, but there is little information on the variables determining this effect.


These studies examined repeated exposure to NLX during extinction of ethanol- or cocaine-induced CPP using both short and long tests.


DBA/2J mice were injected with NLX (0 or 10 mg/kg) before three 10- or 60-min choice extinction tests (experiment 1). All mice received a final 60-min test without NLX. Post-test NLX was given in experiment 2. Experiment 3 tested whether NLX would affect a forced extinction procedure. Experiment 4 tested its effect on extinction of cocaine-induced CPP.


Pre-test (but not post-test) injections of NLX-facilitated choice extinction of ethanol CPP at both test durations. Pre-test NLX also facilitated forced extinction. However, pre-test NLX had no effect on choice extinction of cocaine CPP.


Extinction test duration is not critical for engaging the opioid system during ethanol CPP extinction (experiment 1). Moreover, NLX’s effect does not depend on CPP expression during extinction, just exposure to previously conditioned cues (experiment 3). The null effect of post-test NLX eliminates a memory consolidation interpretation (experiment 2) and the failure to alter cocaine CPP extinction argues against alteration of general learning or memory processes (experiment 4). Overall, these data suggest that the endogenous opioid system mediates a conditioned motivational effect that normally maintains alcohol-induced seeking behavior, which may underlie the efficacy of opiate antagonists in the treatment of alcoholism.

Publisher URL: https://link.springer.com/article/10.1007/s00213-017-4672-z

DOI: 10.1007/s00213-017-4672-z

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.