Nicotine exposure throughout early development promotes nicotine self-administration in adolescent mice and induces long-lasting behavioural changes

Abstract

Maternal cigarette smoking during pregnancy can result in behavioural problems of the offspring. Although the causative agent in tobacco smoke that leads to these aberrations is not known, some studies using animal models have supported the hypothesis that nicotine may cause impairments in fatal and neonatal development. However, in many of the animal studies nicotine has been administered by subcutaneous injections, which could lead to significant fetal hypoxia; some routes of drug administration included stressful procedures to pregnant dams that could create unfavorable fetal environment. In this study, mice were exposed to nicotine via drinking solution. The effects of nicotine exposure throughout early development on behavioural measures during adolescence and adulthood were examined. Adult female dams were allowed to orally self-administer a saccharin, or nicotine plus saccharin solution during gestation and lactation. Following weaning, plasma nicotine concentrations were measured in nicotine-exposed dams, and their offspring were tested using various behavioural measures. [3H]Epibatidine binding was also measured in the cortex and hippocampus at two different time points in the nicotine-exposed adolescents. The results of the study indicate that exposure to nicotine throughout early development influenced intravenous nicotine self-administration, social interactions and performance under a forced swim test. Exposure throughout early development to nicotine however did not affect [3H]epibatidine binding in the hippocampus and cortex.