Nicotine Exposure during the Third Trimester Equivalent of Human Gestation: Time Course of Effects on the Central Cholinergic System of Rats

Up to 22 % of pregnant women smoke, which constitutes a major health concern. Nicotine, a cholinergic agonist, causes deleterious effects on brain development. However, most studies investigate its effects during rodents ’ gestation, which corre-sponds, in terms of neural development, to the first two trimesters of human gestation. Here, we focused on effects of nicotine on the brain cholinergic system during the third trimester equivalent of human gestation. From the 2nd to the 19th day of lactation, dams were exposed either to nicotine (6 mg/kg/day) or to saline via sc osmotic minipumps. Offspring were sacrificed during exposure (PN15, PN, postnatal) or at 2 days (PN21), 11 days (PN30), or 10 weeks (PN90) of withdrawal. In the cerebral cortex, midbrain, and hippocampus, we assessed nicotinic acetylcholine receptor (nAChR) binding, [3H]hemicholinium-3 (HC-3) binding to the high-affinity choline transporter, choline acetyltransferas