Alterations in Septohippocampal Cholinergic Receptors and Related Behavior after Prenatal Exposure to Nicotine

The present study applied the knowledge accumulated in the model for phenobarbital neuroteratogenicity on nicotine. Mice were exposed to nicotine prenatally by injecting the mother 1.5 mg/kg nicotine s.c. twice daily on gestation days 9–18. On age 50 days, the mice were tested in the eight-arm maze and their hippocampi were assayed for muscarinic receptor binding using 3H-QNB as a ligand. Hippocampal muscarinic receptors Bmax of nicotine exposed mice was 58% higher than control (p < 0.05). On the other hand, Kd was unaffected by prenatal nicotine exposure. Nicotine-exposed mice made 26% more errors in the maze than control (p < 0.01). The study suggests that nicotine administered to the fetus alters septohippocampal chemistry and induces deficits in hippocampus related behavior. The possible lineal relationship between these two changes is the subject of our current investigations.