 |
| Figure 7 (al'Absi et al., 2014) |
Hormones typically associated with
hunger and satiety, such as ghrelin, leptin, and peptide YY, may also function
in nicotine craving and reward. High peptide YY levels were associated with
lower craving for nicotine and increased positive affect in abstinent smokers,
with an overall result of lower desire to alleviate withdrawal symptoms
(al’Absi, Lemieux, & Nakajima, 2014). Ghrelin did not follow the same trend,
but ghrelin levels predicted risk of relapse with a positive relationship (Figure
7). Ghrelin is believed to interact with
nicotinic acetylcholine receptors to enhance dopamine in the reward circuit and
make the reinforcing effects of nicotine more salient (al’Absi et al., 2014). This is consistent with other literature
explaining ghrelin activating the reward pathway through cholinergic links.
(Engel & Jerlhag, 2014). The details
of this mechanism are still being examined.
Zoli and Picciotto (2012) examined the role of nicotine in energy homeostasis. Cigarette smoke exposure results in inhibition of NPY in the PVN, which would result in inhibited food intake. Evidence for the relationship between leptin and nicotine has been sparse and inconclusive. Varying doses, styles of administration, and food restrictions have yielded different results on the relation between nicotine and leptin (Zoli & Picciotto, 2012). Leptin is thought to be involved with weight changes associated with chronic smoking and abstinence. Perkins and Fonte (2002) report male and female smokers had a significant increase in weight 3 weeks after quitting smoking. Leptin levels were increased in women, but there were no changes in men. The researchers expected for leptin levels to decrease and stimulate hunger rather than increase, so the effect of nicotine on weight was not attributed to changes in leptin.
Hunger and satiety hormones need greater investigation to
gain a clear grasp in their role on nicotine craving and reward. Ghrelin and peptide YY seem to relate to withdrawal
symptoms and maintained abstinence versus relapse (al’Absi et al., 2014). These hormones can potentially aid in the
development of different smoking cessation methods. It is unclear if leptin is related to these
concepts or has an association with weight changes of smoking and abstinence
(Perkins & Fonte, 2002). Research
into these hormones need more evidence and the mechanism of action must be
explored.
