[Abstract Title]. - Society for Neuroscience

Do Rio Grande do Sul, Porto Alegre, Brazil; 4 Section of Behav Pharmacol, Inst. Psych, Kings
Col. London P049, London, United Kingdom
Abstract: Inattention, hyperactivity, and poor impulse control (impulsivity) are the main
characteristics of Attention-Deficit Hyperactivity Disorder (ADHD). About 60% of children
diagnosed with ADHD retain the condition as adults. The aetiology of the disorder is not known.
Recently, maternal cigarette smoking during pregnancy has been proposed as a risk factor for
ADHD. Attention and impulsivity deficits in humans can be assessed by the continuous
performance test (CPT) requiring responding to a specific visual stimulus. Children with ADHD
show overall lower scores on this test due to increased impulsivity and inattention. The
preclinical analogue of the CPT is the 5-choice serial reaction time test (5-CSRTT) that is
performed in an operant chamber with one curved wall containing a horizontal array of five
apertures. Nose-pokes into a briefly illuminated aperture are reinforced with food. This visual
discrimination paradigm involves sustained, selective and divided attention, and impulsivity to
varying extents, depending upon the scheduled task demands. Here we present the first
experimental evidence of a link between prenatal exposure to nicotine and increased
inattentiveness and impulsivity in adult rats. Pregnant Lister hooded rats consumed nicotine
solution (0.06 mg/ml) throughout pregnancy as the only source of drinking water. The mean
nicotine daily consumption was 4.2±0.5 mg/kg body weight. Weight loss in females exposed to
nicotine was not more than 15%, the consequences of which need further investigation. Male
offspring of these females were tested in adulthood using the 5-CSRTT. There was no difference
between control- and nicotine- exposed animals during acquisition; however, at the final stage
when a 1 s stimulus duration was used, the performance of rats prenatally exposed to nicotine
was compromised during the first twelve days of training. These rats displayed decreased
accuracy (inattentiveness; 77.1±3.5 vs. 84.9±2, p