Present address: St. Jude Children’s Research Hospital, 332 N. Lauderdale, Memphis, TN 38105, USA.
Prenatal nicotine exposure changes natural and drug-induced reinforcement in adolescent male rats
Version of Record online: 28 JUN 2008
© The Authors (2008). Journal Compilation © Federation of European Neuroscience Societies and Blackwell Publishing Ltd
European Journal of Neuroscience
Volume 27, Issue 11, pages 2952–2961, June 2008
How to Cite
Franke, R. M., Park, M., Belluzzi, J. D. and Leslie, F. M. (2008), Prenatal nicotine exposure changes natural and drug-induced reinforcement in adolescent male rats. European Journal of Neuroscience, 27: 2952–2961. doi: 10.1111/j.1460-9568.2008.06253.x
- Issue online: 28 JUN 2008
- Version of Record online: 28 JUN 2008
- Received 29 August 2007, revised 6 March 2008, accepted 8 April 2008
Clinical studies have demonstrated an increased incidence of substance misuse and obesity in adolescents whose mothers smoked during pregnancy. Although dopamine systems that mediate natural and drug-induced reinforcement have been shown in animal studies to be altered by gestational nicotine treatment, it is not clear whether there are concomitant changes in reinforcement sensitivity. To test whether prenatal nicotine exposure influences sensitivity to natural and drug rewards, timed pregnant rats were implanted with osmotic minipumps delivering saline or nicotine (3 mg/kg/day) from gestational day 4 to 18. Male offspring were tested as adolescents, on postnatal day 32, for operant responding maintained by sucrose pellets or i.v. cocaine (200 or 500 μg/kg per injection). Cocaine-induced stereotypy and c-fos mRNA expression in cortex and striatum were also examined. Complex changes in reward circuitry were observed in the offspring of nicotine-exposed dams. Nicotine-exposed adolescents did not self-administer the low dose of cocaine, but, at the higher dose, exhibited significantly greater cocaine intake and c-fos mRNA expression in nucleus accumbens than did controls. In contrast, control animals showed significantly greater drug-induced stereotypy at both cocaine doses. Operant responding maintained by sucrose was also influenced by gestational nicotine exposure. At a fixed ratio (FR) 1 schedule, although the number of pellets eaten by the two experimental groups was equivalent, more pellets were left uneaten by nicotine-exposed offspring. At FR2 and FR5 schedules, the responding maintained by sucrose pellets was lower in nicotine-exposed offspring. These findings suggest that nicotine exposure during gestation may induce changes in both natural and drug reward pathways.