Hyperactivity induced by prenatal nicotine exposure is associated with an increase in cortical nicotinic receptors

Prenatal exposure to nicotine may lead to hyperactivity. To evaluate possible involvement of central nicotinic receptors in this condition, pregnant Sprague-Dawley rats were implanted with osmotic minipumps to receive nicotine (6 mg/kg/day) or saline throughout gestation. A total of 222 pups (118 males and 104 females) from 24 dams were measured for locomotor activity. Male and female hyperactive and nonhyperactive offspring from each treatment group were selected and analyzed for nicotinic receptor concentrations in various brain regions. Hyperactive male offspring that were prenatally exposed to nicotine exhibited a significant increase in the cortical receptor densities without a change in binding affinity. Hyperactive offspring of saline-treated dams did not show an increase in cortical nicotinic receptors. These results suggest that hyperactive male offspring of nicotine-exposed dams are also susceptible to neurochemical effects of intrauterine nicotine exposure.