Fig. 5.   Effects of nicotine infusions throughout gestation on biomarkers of cell damage (ornithine decarboxylase activity, ODC) and cell number (DNA content) evaluated in postnatal rat brain (Slotkin et al., 1987c). Nicotine exposure elicits persistent damage and cell loss despite discontinuation of nicotine exposure at birth. Effects are discernible in both an early-developing region (forebrain) and late-developing region (cerebellum).