title: Early adolescent nicotine exposure affects later-life cocaine reward in mice.
abstract: Adolescence represents a unique developmental period associated with increased risk-taking behavior and experimentation with drugs of abuse, in particular nicotine. We hypothesized that exposure to nicotine during early adolescence might increase the risk for drug reward in adulthood. To test this hypothesis, male ICR mice were treated with a subchronic regimen of nicotine or saline during adolescence, and their preference for cocaine, morphine and amphetamine was examined using the conditioned place preference (CPP) test in adulthood. Long-term behavioral changes induced by nicotine suggested a possible role of altered gene transcription. Thus, immunoblot for ΔFosB, a member of the Fos family of transcription factors, was conducted in the nucleus accumbens of these mice. Mice treated with nicotine during early but not late adolescence showed an increase in CPP for cocaine, morphine and amphetamine later in adulthood. This effect was not seen in mice pretreated with a subchronic regimen of nicotine as adults, suggesting that exposure to nicotine specifically during early adolescence increases the rewarding effects of other drugs in adulthood. However, adolescent nicotine exposure did not alter highly palatable food conditioning in mice. The enhancement of cocaine CPP by nicotine was strain-dependent and was blocked by pretreatment with nicotinic antagonists. In addition, nicotine exposure during early adolescence induced ΔFosB expression to a greater extent than identical nicotine exposure in adulthood, and enhanced cocaine-induced locomotor sensitization later in adulthood. These results suggest that nicotine exposure during early adolescence increases drug-induced reward in adulthood through mechanisms that may involve the induction of ΔFosB.
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Mai
authors.initials: M
authors.lastname: Alajaji
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Lazenka
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Dena
authors.initials: D
authors.lastname: Kota
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Wise
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Rabha M
authors.initials: RM
authors.lastname: Younis
authors.affiliation: Center for Drug Discovery, Research Triangle Institute, PO Box 12194, Research Triangle Park, NC 27709-2194, USA.
authors.forename: F Ivy
authors.initials: FI
authors.lastname: Carroll
authors.affiliation: Columbia University, Department of Psychiatry, New York, NY 10032, USA.
authors.forename: Amir
authors.initials: A
authors.lastname: Levine
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Dana E
authors.initials: DE
authors.lastname: Selley
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Sim-Selley
authors.affiliation: Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Medical Campus, Virginia Commonwealth University, Richmond, VA 23298-0613, USA. Electronic address: m.damaj@vcuhealth.org.
authors.forename: M Imad
authors.initials: MI
authors.lastname: Damaj
mesh_terms: D000375:Aging / Q000523:psychology; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003216:Conditioning, Operant; D004435:Eating / Q000187:drug effects; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics; D012201:Reward
chemical_list: D000697:Central Nervous System Stimulants; D009294:Narcotics; D018722:Nicotinic Agonists; D016760:Proto-Oncogene Proteins c-fos; D009538:Nicotine; D009020:Morphine; D000661:Amphetamine; D003042:Cocaine
keywords: Adolescence; Cocaine; DeltafosB; Mice; Nicotine; Reward