Increased drug seeking and vulnerability to relapse after escalation of nicotine intake by dose manipulation in male and female rats
摘要
Nicotine addiction is characterized by escalated drug use, craving and a high relapse rate after abstinence. 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.
ResultsHere 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.
ConclusionsOverall, this study shows that most of the behavioral changes observed following escalation of nicotine self-administration are similar to those previously observed with other drugs of abuse.