title: Combined exposure to tobacco smoke and ethanol in adolescent mice elicits memory and learning deficits both during exposure and withdrawal.
abstract: BACKGROUND
  Adolescents often associate tobacco smoking and consumption of alcoholic beverages. In spite of that, little is known about the neurobehavioral consequences of the dual exposure in the adolescent brain. In the present work, we assessed the effects of tobacco smoke and/or ethanol exposure during adolescence on memory/learning.
  
  
  METHODS
  From postnatal day 30 to 45 (PN30-45), male and female Swiss mice were exposed to tobacco smoke (SMK-generated from research cigarettes type 3R4F, whole body exposure, 8hr/day) and/or ethanol (ETOH-25% solution, 2g/kg intraperitoneally injected every other day) as follows: (a) SMK+ETOH exposure; (b) SMK exposure; (c) ETOH exposure; (d) Control. Memory/learning was evaluated during exposure (PN44-45) and during short- (PN49-50) and long-standing withdrawal (PN74-75). At each timepoint, mice were trained and tested in a step-down passive avoidance task (0.3 mA, 3 s footshock). Two retention tests were carried out in each animal, one at 3hr after training to measure short-term memory and another at 24hr to measure long-term memory.
  
  
  RESULTS
  During exposure, the short-term memory was impaired in all groups and the long-term memory was impaired in SMK and SMK+ETOH. During the short-standing withdrawal, a significant impairment was observed only in long-term memory of the male SMK+ETOH mice. At long-standing withdrawal, there were no significant differences between groups.
  
  
  CONCLUSIONS
  Tobacco smoke and ethanol exposures during adolescence of mice negatively affect learning/memory performance. Deficits that were still present during SMK+ETOH short-standing withdrawal suggest that the combined exposure elicits a worsened memory/learning outcome and that males are more susceptible.
authors.affiliation: Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Centro Biomédico, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, 20550-170, Brazil. yael_a_v@yahoo.com.br
authors.forename: Yael
authors.initials: Y
authors.lastname: Abreu-Villaça
authors.forename: Anna Caroline
authors.initials: AC
authors.lastname: de Carvalho Graça
authors.forename: Anderson
authors.initials: A
authors.lastname: Ribeiro-Carvalho
authors.forename: Victor de Freitas
authors.initials: Vde F
authors.lastname: Naiff
authors.forename: Alex C
authors.initials: AC
authors.lastname: Manhães
authors.forename: Cláudio C
authors.initials: CC
authors.lastname: Filgueiras
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001835:Body Weight; D003367:Cotinine / Q000097:blood; D000431:Ethanol / Q000097:blood / Q000633:toxicity*; D005260:Female; D007858:Learning / Q000187:drug effects*; D008297:Male; D057567:Memory, Long-Term / Q000187:drug effects*; D008570:Memory, Short-Term / Q000187:drug effects*; D051379:Mice; D012907:Smoking / Q000009:adverse effects*; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology / Q000523:psychology
chemical_list: D000431:Ethanol; D003367:Cotinine