In addition, the developmental neurotoxicity of nicotine produces changes that promote resistance to oxidative stress, including marked reductions in synaptic development and activity, and the replacement of damaged neurons with glia, cells that possess major antioxidant pathways (Levin and Slotkin 1998; Roy et al. 2002; Slotkin 1998, 2004; Slotkin et al. 2005; Tanaka et al. 1999).