Abstract
The ability of morphine to support a conditioned place preference (CPP) in preweanling (18-22-day-old) and adult (70-90-day-old) rats was assessed. Prior to a 15-min compartment preference test, subjects received a saline-paired, 30-min exposure to a distinct compartment 2 h prior to receiving an injection of 1 or 5 mg/kg of morphine or saline, paired with a 30-min exposure to an alternate compartment for 4 consecutive days. Although overall activity levels differed substantially across age, preweanling and adult rats displayed similar patterns of activity during conditioning. Moreover, only adults exhibited a significant sex difference; females were more active than were males following an injection of 5 mg/kg of morphine. Both doses of morphine supported a comparable CPP in preweanlings and adults, and both ages exhibited relatively low activity levels while in the morphine-paired compartment. These similarities across age suggest that the CPP procedure may prove to be useful in elucidating the ontogeny of learning, memory, and stimulus selection in rats.
Original language | English |
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Pages (from-to) | 217-222 |
Number of pages | 6 |
Journal | Pharmacology Biochemistry and Behavior |
Volume | 60 |
Issue number | 1 |
DOIs | |
State | Published - May 1998 |
Keywords
- CPP
- Conditioned place preference
- Morphine
- Ontogeny
- Rattus norvegicus
ASJC Scopus subject areas
- Biochemistry
- Toxicology
- Pharmacology
- Clinical Biochemistry
- Biological Psychiatry
- Behavioral Neuroscience