title: Effect of forced chronic oral nicotine exposure on intravenous self-administration and rewarding properties of acute nicotine.
abstract: The effect of 7-week forced oral nicotine exposure on acquisition of intravenous nicotine self-administration, nicotine place conditioning, and nicotine preference was studied in mice. The nicotine solution was given in stepwise increased concentrations as the sole source of liquid for 7 weeks. Nicotine exposed animals self-administered nicotine intravenously at lower unit dose than nicotine-naïve ones, indicating that the forced 7-week nicotine exposure, followed by 7-day withdrawal, had rendered them more sensitive to nicotine's reinforcing effects. At the dose of 0.5 mg/kg, nicotine induced conditioned place preference both in drug-naïve and nicotine exposed mice, but the 0.3 mg/kg dose of nicotine failed to do so. The forced nicotine pre-exposure did not alter the nicotine preference in the 2-bottle free-choice paradigm. In conclusion, these results suggest that nicotine pre-exposure enhances the reinforcing effects of acutely administered nicotine only in the intravenous self-administration model.
authors.affiliation: Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, Finland. anne.tammimaki@helsinki.fi
authors.forename: Anne
authors.initials: A
authors.lastname: Tammimäki
authors.forename: Vladimir
authors.initials: V
authors.lastname: Chistyakov
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Patkina
authors.forename: Johanna
authors.initials: J
authors.lastname: Skippari
authors.forename: Liisa
authors.initials: L
authors.lastname: Ahtee
authors.forename: Edwin
authors.initials: E
authors.lastname: Zvartau
authors.forename: Pekka T
authors.initials: PT
authors.lastname: Männistö
mesh_terms: D000284:Administration, Oral; D000818:Animals; D021461:Animals, Outbred Strains; D003216:Conditioning, Operant / Q000187:drug effects*; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D012201:Reward; D012646:Self Administration; D014029:Tobacco Use Disorder
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine