Repeated paired-testing impairs extinction of morphine-induced conditioned place preference dependent on the inter-test interval in rats

Neurosci Lett. 2012 May 10;516(1):72-4. doi: 10.1016/j.neulet.2012.03.060. Epub 2012 Mar 29.


Using exposure to morphine- and saline-paired sides alternatively as the extinction training procedure, we find that post-retrieval extinction training enhances or hinders the extinction of morphine-induced conditioned place preference (CPP) dependent on the retrieval-extinction training intervals. Here, we examine the influence of post-retrieval extinction training with repeated paired testing on extinction of morphine-induced CPP of rats. Our results demonstrate that paired-testing with a 10-min inter-test interval does not influence the extinction of CPP, while post-retrieval extinction training blocks the extinction of CPP with a 3-h retrieval-extinction interval. These results strongly indicate that the interval between exposure trials influences the outcome of exposure therapy in addiction treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Choice Behavior / drug effects*
  • Choice Behavior / physiology*
  • Conditioning, Psychological / drug effects*
  • Conditioning, Psychological / physiology*
  • Extinction, Psychological / drug effects*
  • Extinction, Psychological / physiology*
  • Male
  • Morphine / pharmacology*
  • Rats
  • Rats, Sprague-Dawley


  • Morphine