Psychopharmacology

, Volume 103, Issue 2, pp 183–186

Role of repeated exposure to morphine in determining its affective properties: place and taste conditioning studies in rats

Authors

  • M. Gaiardi
    • Institute of PharmacologyUniversity of Bologna
  • M. Bartoletti
    • Institute of PharmacologyUniversity of Bologna
  • A. Bacchi
    • Institute of PharmacologyUniversity of Bologna
  • C. Gubellini
    • Institute of PharmacologyUniversity of Bologna
  • M. Costa
    • Institute of PharmacologyUniversity of Bologna
  • M. Babbini
    • Institute of PharmacologyUniversity of Bologna
Original Investigations

DOI: 10.1007/BF02244201

Cite this article as:
Gaiardi, M., Bartoletti, M., Bacchi, A. et al. Psychopharmacology (1991) 103: 183. doi:10.1007/BF02244201

Abstract

Male Sprague Dawley rats were injected daily with saline (morphine naive rats) or 20 mg/kg morphine (morphine experienced rats), starting at least 12 days before training. Subsequent place and taste conditioning indicated that 2.5 mg/kg morphine caused a significant increase in the amount of time spent on the least preferred side by morphine experienced but not by morphine naive rats; furthermore, saccharin consumption was markedly decreased and slightly increased by 10–20 mg/kg morphine in naive and experienced rats, respectively. It was concluded that morphine experience enhances the reinforcing efficacy of morphine and broadens the conditions under which the drug is reinforcing; thus it possibly increases morphine abuse potential.

Key words

Sensitization to drug rewardMorphinePlace conditioningTaste conditioningAbuse potentialRat
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Copyright information

© Springer-Verlag 1991