Objective: Preclinical data suggest modulating effects of both orexin/hypocretin and leptin on dopaminergic transmission in mesolimbic reward pathways. This indicates a possible role of both peptides in reward function and motivation, and thus in addictive diseases. The aim of this study was to examine the possible association between orexin and leptin, and nicotine craving in smokers in a clinical case-control study under standardized conditions.
Methods: We compared orexin and leptin, ACTH and cortisol plasma concentrations (RIA) between tobacco smokers (n=60) during early nicotine withdrawal and healthy controls (n=64). Motivational aspects of nicotine craving were additionally assessed in the smoking participants using the Questionnaire of Smoking Urges (QSU).
Results: As main results we detected a significant negative correlation between orexin plasma concentration and nicotine craving (r=-0.28; p<.05), and a positive association between craving and leptin plasma concentration (r=0.29; p<.05).
Conclusions: Our results show an association between craving for nicotine and plasma concentrations of orexin and leptin suggesting that both peptides interfere with the dopaminergic transmission during nicotine withdrawal in a bidirectional manner and, thus, modulate craving for nicotine.
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