Exposure to tobacco smoke containing either high or low levels of nicotine during adolescence: differential effects on choline uptake in the cerebral cortex and hippocampus.
BACKGROUND
There is a lack of experimental studies that investigate the effects of tobacco smoke exposure during adolescence. Here, we investigated the effects of tobacco smoke generated from cigarettes containing either high or low levels of nicotine on the cholinergic system.


METHODS
From postnatal day (PN) 30 to 45, 18 C57BL/6 (inbred) and 16 Swiss (outbred) mice of both sexes were exposed to tobacco smoke (whole body exposure for 8 hr/day and 7 days/week) generated from one of two reference research cigarettes: type 3R4F (HighNIC group-nicotine = 0.73 mg/cigarette) or type 4A1 (LowNIC group-nicotine = 0.14 mg/cigarette). Control mice (CT) were exposed to air. On PN 45, cotinine (nicotine metabolite) serum levels and [(3)H]choline uptake in the cerebral cortex and hippocampus were assessed.


RESULTS
Cotinine serum levels were eight times higher in HighNIC mice (C57BL/6:142.0 +/- 16.7 ng/ml and Swiss: 197.6 +/- 11.1 ng/ml) when compared with LowNIC ones (C57BL/6:17.4 +/- 7.4 ng/ml and Swiss: 24.6 +/- 2.2 ng/ml). Only HighNIC mice presented a significant increase in [(3)H]choline uptake in the hippocampus (C57BL/6: HighNIC > CT and HighNIC > LowNIC, p < .001 and Swiss: HighNIC > CT and HighNIC > LowNIC, p < .001), whereas in the cerebral cortex, both HighNIC and LowNIC mice presented increased [(3)H]choline uptake (C57BL/6: HighNIC > CT and LowNIC > CT, p < .05 and Swiss: HighNIC > CT and LowNIC > CT, p < .001).


CONCLUSIONS
Our results indicate that tobacco smoke exposure during adolescence increases [(3)H]choline uptake. However, the effects are dependent on the type of cigarette and on the brain region.
Abreu-Villaça
Yael
Y
Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Centro Biomédico, Universidade do Estado do Rio de Janeiro, Av. Prof. Manoel de Abreu 444, 5 degrees andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil. yael_a_v@yahoo.com.br
Filgueiras
Cláudio Carneiro
CC
Guthierrez
Monique
M
Medeiros
Ana Heloisa de
AH
Mattos
Maria Angélica
MA
Pereira
Maurício Dos Santos
Mdos S
Manhães
Alex Christian
AC
Kubrusly
Regina Célia Cussa
RC
D000293:Adolescent; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D018678:Cholinergic Agents / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009538:Nicotine / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects*; D012741:Sexual Maturation / Q000187:drug effects; D012906:Smoke
D002492:Central Nervous System Depressants; D018678:Cholinergic Agents; D012906:Smoke; D009538:Nicotine; D002795:Choline O-Acetyltransferase