Date of Award

2026-08-01

Degree Name

Doctor of Philosophy

Department

Psychology

Advisor(s)

Laura E. O'Dell

Abstract

The increasing prevalence of electronic cigarette (e-cigarette) use among adolescents highlights the need to identify factors that promote nicotine vapor use in populations most susceptible to its long-term consequences. This requires translationally relevant animal models of nicotine vapor self-administration (VSA). Accordingly, the goal of this dissertation was to evaluate 2 key factors hypothesized to influence nicotine VSA in rats, including age and e-liquid vehicle composition. Given recent mandates on studying sex as a biological variable, the present work included both female and male rats. Aim 1 compared VSA behavior during adolescence (adolescent-onset) or adulthood (adult-onset) in groups that received vapor plumes composed of vehicle or Vehicle + Nicotine. Nose-poke responses were also compared in the Vehicle + Nicotine groups during extinction training and reinstatement testing. Aim 2 assessed the same measures in separate groups of adolescent-onset rats that received e-liquid vehicles composed of propylene glycol (PG) and vegetable glycerin (VG) in different ratio combinations (80:20, 50:50, 20:80, or 0:100 PG:VG). Both aims assessed cotinine (the primary metabolite of nicotine) levels to evaluate group differences in systemic nicotine delivery. Aim 1 revealed that adolescent-onset rats displayed higher VSA behavior than adults, and their nicotine intake was correlated with cotinine levels. Adolescent-onset rats also displayed more nicotine-seeking behavior during extinction and reinstatement than adults. Aim 2 revealed that adolescent-onset rats that received the 50:50 PG:VG ratio produced high levels of nicotine VSA that were correlated with their cotinine levels. Rats that received the 0:100 PG:VG ratio displayed the lowest levels of nicotine intake and cotinine relative to the other ratios. Collectively, these findings demonstrate that age and vehicle composition influence nicotine VSA behavior, and these key factors likely promote vulnerability to e-cigarette use among adolescents.

Language

en

Provenance

Received from ProQuest

File Size

67 p.

File Format

application/pdf

Rights Holder

Tiffany Alexandra Gonzalez-Gutierrez

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