High-dose adolescent nicotine exposure permits spontaneous nicotine self-administration in adult male rats

Abstract

Introduction: While cigarette smoking rates have been steadily decreasing over the past decade, there has been a dramatic increase in nicotine use via e-cigarettes, especially during adolescence. Adolescent e-cigarette use is associated with a greater risk of future cigarette smoking, and increased rates of cigarette smoking in individuals who may have otherwise never tried cigarettes. In humans and rodents, early initiation of nicotine use has been associated with greater consumption, dependence, and persistent nicotine use. The present study sought to investigate the long-lasting effect of daily high-dose nicotine exposure during adolescence on nicotine consumption in adulthood.Method: Male Sprague-Dawley rats were exposed daily to nicotine (1.0 mg/kg, subcutaneous), or vehicle (1 ml/kg saline, subcutaneous) during adolescence (post-natal day [P] 28-41). Adult nicotine self-administration (0.02 mg/kg/infusion, intravenous) was assessed beginning on P75 on fixed-ratio 1 (FR1), fixed-interval 1min (FI1), and progressive ratio (PR) schedules of reinforcement.Results: Adolescent nicotine pre-exposure did not affect adult nicotine self-administration on the simple FR1 schedule, however increased intake and responding for nicotine was observed when a short delay was implemented on an FI1 schedule of reinforcement. Conclusions:Adolescence is a critical period when the brain is especially vulnerable to the effects of nicotine. Nicotine exposure in adolescence enhances susceptibility to increased nicotine ✉

Adult consequences of repeated nicotine vapor inhalation in adolescent rats

“…There is evidence that nicotine injection during adolescence alters responses in rats during adulthood. For example, Renda and colleagues found that male rats treated with nicotine (1.0 mg/kg, s.c.) once daily from Post-Natal Day (PND 28-41) did not intravenously self-administer more nicotine as adults under initial Fixed Ratio (FR1) or a Progressive Ratio contingency, but did self-administer slightly more under a Fixed-Interval 1 minute procedure (Renda et al, 2020). Cardenas and Lotfipour (Cardenas and Lotfipour, 2022) reported increased self-administration of methamphetamine in male rats treated with nicotine by i.v.…”

Adolescent nicotine administration impacts working memory and reversal learning but not cognitive flexibility

“…Nicotine exposure during a development period analogous to adolescence enhances self-administration and conditioned place preference (Adriani et al, 2002;Vastola et al, 2002). Similar studies have found that exposure to nicotine in adolescence, when compared to later developmental periods, significantly increased motivation to work for nicotine self-administration (Adriani et al, 2003;Renda et al, 2020).…”

FARESHARE: An open-source apparatus for assessing drinking microstructure in socially housed rats

“…However, it is difficult to track individual differences in consumption when animals share a cage and a common substance source. The majority of drug intake studies in rodents have required social isolation of subjects to get around this issue, neglecting the social context so relevant to clinical populations [2,11]. Radio frequency tracking is one promising solution and has been used in commercial products such as IntelliCage.…”