Storm, Stress, and Nicotine: Examining the interactive effects of adolescent stress and adolescent nicotine on the development of long-term learning deficits

Abstract

In order to continue the decline of smoking prevalence, it is imperative to understand the factors that contribute to the development of nicotine and tobacco addiction, such as adolescent initiation of nicotine use, stress, and the interaction of adolescent stress and adolescent nicotine. Both clinical and preclinical literature indicates that adolescent, but not adult, nicotine administration leads to long-lasting impairments in learning and memory and affect. Specifically, chronic nicotine treatment beginning in early adolescence or late adolescence resulted in adult deficits in contextual fear learning. However, the current study demonstrated that these adult learning deficits did not occur solely from nicotine administration. Rather, an interaction between adolescent nicotine and adolescent stress resulted in adult learning deficits in contextual fear. Additionally, it was found that dietary choline supplementation that began immediately following cessation of adolescent nicotine treatment and continued through a protracted abstinence period lasting thirty days reversed adult deficits in contextual fear. Finally, the current study found that adolescent nicotine exposure beginning at either early adolescence or late adolescence increased depressive-like behaviors, but not anxiety-like behaviors, following a protracted abstinence period. In contrast, chronic nicotine treatment in adult increased anxiety-like behaviors measured by the elevated plus-maze following a protracted abstinence period. The work encompassed in this dissertation suggests that the interactions between adolescent stress and adolescent nicotine increases the risk for developing cognitive and affective impairments, which may promote continued use of nicotine in adulthood.