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bioRxiv · 10.1101/2025.09.14.676091

Increased drug-seeking and vulnerability to relapse after escalation of nicotine intake in male and female rats

Letort, K.·Lageyre, L.·Ahmed, S. H.·Guillem, K.
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Abstract

Nicotine addiction is characterized by escalated drug use, craving and a high relapse rate after abstinence. However, because of difficulties in demonstrating escalation of nicotine use in rats, its relation to other addiction-related phenomena is currently unknown. Recently, we showed that, compared to rats with a fixed moderate dose of nicotine, rats with access to increasing high doses of nicotine for self-administration progressively escalated their nicotine intake. Whether these animals with escalating patterns of nicotine self-administration also develop other behavioral signs of addiction remains to be investigated. Here we report that after escalation of nicotine intake, animals have a greater difficulty of abstaining from seeking the drug, a greater responsiveness to nicotine-induced craving-like behavior, and an increased vulnerability to re-escalate nicotine intake post-extinction than rats with stable patterns of nicotine intake. No substantial sex differences in the development of these different addiction-related phenomena were observed. Finally, after escalation, nicotine intake also became primarily dependent on nicotine reinforcement and less so on the nicotine-paired cue. Overall, this study shows that most of the post-escalation behavioral changes previously seen with other drugs of abuse are generalizable to nicotine intake escalation.

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Letort, K., Lageyre, L., Ahmed, S. H., Guillem, K.. 2025-09-17. Increased drug-seeking and vulnerability to relapse after escalation of nicotine intake in male and female rats. https://doi.org/10.1101/2025.09.14.676091

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