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

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.

• Authors: M Gaiardi, M Bartoletti, A Bacchi, C Gubellini, M Costa, M Babbini
• Journal: Psychopharmacology (Psychopharmacology (Berl)) Vol. 103 Issue 2 Pg. 183-6 ( 1991) ISSN: 0033-3158 [Print] Germany
• PMID: 2027919 (Publication Type: Journal Article)

Chemical References

• Morphine
• Saccharin

Topics

• Animals
• Conditioning, Operant (drug effects)
• Emotions (drug effects)
• Male
• Morphine (pharmacology)
• Rats
• Rats, Inbred Strains
• Saccharin (pharmacology)
• Taste (drug effects)