The effects of totigestational exposure to nicotine on pre- and postnatal development in the rat.

Chronic administration of low doses of nicotine (1.5 and 3 mg/kg per day) to female Fischer 344 rats started one week prior to mating and continued until parturition. An initial dose-related weight reduction was seen during the first week. However, following mating the weight gain of the females and the birth weight of the offspring were not different from controls. Treatment effects in the newborn were observed in the righting reflex, temperature regulation, adherence to the inclined screen, and in organ/body weight ratios for brain, heart, lung, liver, and kidney. In the adult female offspring treatment-related effects were seen as a prolonged time required and an increase in number of mistakes made, during food maze testing and an increased brain protein content. Treated offspring required three learning sessions to reach the 50% shock avoidance level while control offspring required only two. Nicotine administered chronically in low doses throughout gestation has little effect on gross structural development, but does cause subtle neurological changes which are manifested as behavioral alterations in the newborn and adult offspring.