Tobacco smoke containing high or low levels of nicotine during adolescence: effects on novelty-seeking and anxiety-like behaviors in mice.
BACKGROUND
Thousands of adolescents start smoking daily but information on the effects of tobacco exposure on this age group is scarce. Moreover, the available animal models rely on the effects of nicotine, neglecting other neuroactive components of tobacco.


OBJECTIVE
We investigated the effects of exposure of adolescent mice to tobacco smoke generated from cigarettes containing either high or low levels of nicotine on novelty seeking and anxiety-like behaviors.


METHODS
From postnatal day (PN) 30 to 45, male and female Swiss mice were exposed to tobacco smoke (whole body exposure, 8 h/day, 7 days/week) generated from 2R1F (HighNic group: 1.74 mg nicotine/cigarette) or 4A1 (LowNic group: 0.14 mg nicotine/cigarette) research cigarettes, whereas control mice were exposed to ambient air. By the end (PN44-45), shortly (PN49-50), or long after (PN74-75) exposure, mice were tested on the elevated plus maze and on the hole board.


RESULTS
While HighNic mice presented an increased number of head-dips (increased novelty-seeking) and decreased grooming (increased anxiety-like behavior) by the end of adolescent exposure, only the latter effect persisted shortly after its end. Distinctively, LowNic mice presented reduced head-dips both by the end and shortly after exposure as well as decreased grooming shortly and long after the end of exposure. Interestingly, only HighNic mice presented detectable cotinine (nicotine metabolite) serum levels (109.1 ± 24.0 ng/ml).


CONCLUSIONS
Our results demonstrate that even adolescent exposure to tobacco smoke with very low nicotine content can have significant short- and long-term behavioral effects, supporting the hypothesis that adolescents can be particularly vulnerable to the effects of cigarette consumption.
Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar - Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil, yael_a_v@yahoo.com.br.
Yael
Y
Abreu-Villaça
Cláudio C
CC
Filgueiras
Monique
M
Correa-Santos
Cristiane C
CC
Cavina
Victor F
VF
Naiff
Thomas E
TE
Krahe
Alex C
AC
Manhães
Anderson
A
Ribeiro-Carvalho
D000293:Adolescent; D000818:Animals; D001007:Anxiety / Q000097:blood / Q000139:chemically induced* / Q000523:psychology*; D003367:Cotinine / Q000097:blood; D005106:Exploratory Behavior / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D009538:Nicotine / Q000008:administration & dosage* / Q000633:toxicity; D012906:Smoke; D012907:Smoking / Q000009:adverse effects / Q000097:blood; D014026:Nicotiana
D012906:Smoke; D009538:Nicotine; D003367:Cotinine