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Prenatal oxazepam effects on cocaine conditioned place preference in developing mice
G Dell'omo1, G Laviola, F Chiarotti
1Section of Behavioural Pathophysiology, Istituto Superiore di Sanità, Roma, Italy.
Neurotoxicology and Teratology
|May 1, 1993
Summary
Prenatal oxazepam exposure enhanced cocaine-induced place preference in young mice, but did not alter locomotor activity development. This suggests oxazepam may prime the developing brain for later drug reinforcement.
Area of Science:
- Neuroscience
- Developmental Psychology
- Pharmacology
Background:
- Prenatal exposure to certain medications can impact neurodevelopment.
- Cocaine's reinforcing effects are mediated by dopamine pathways, which mature postnatally.
- Oxazepam is a benzodiazepine anxiolytic with potential effects on developing neurotransmitter systems.
Purpose of the Study:
- To investigate the long-term effects of prenatal oxazepam (OX) exposure on cocaine's reinforcing and activity-enhancing properties in developing mice.
- To determine if prenatal OX alters the age-dependent development of cocaine's effects.
Main Methods:
- Outbred CD-1 mouse pups were prenatally exposed to oxazepam or vehicle.
- Cocaine's (0, 5, 25 mg/kg) positively reinforcing effects were assessed using a 4-day conditioned place preference (CPP) paradigm.
- Locomotor activity was measured at three developmental ages (14-17, 21-24, 28-31 days).
Main Results:
- A single 25 mg/kg cocaine dose produced CPP in 28-31 day-old mice regardless of prenatal treatment.
- Younger mice (14-24 days) exposed prenatally to OX showed significant cocaine CPP, unlike vehicle-exposed controls.
- Prenatal OX did not substantially alter the developmental trajectory of cocaine-induced locomotor activity enhancement.
Conclusions:
- Prenatal oxazepam exposure sensitizes the developing mouse brain to the reinforcing effects of cocaine at younger ages.
- This sensitization is specific to the reinforcing properties, as locomotor activity development remains largely unchanged.
- Findings suggest prenatal exposure to anxiolytics may prime the brain for increased vulnerability to psychostimulant reinforcement later in development.