Figure 1.

Mechanisms by which nicotine reduces body weight. Nicotine activates α3β4 nAChRs on POMC neurons in the arcuate nucleus, which then project to the paraventricular nucleus of the hypothalamus, where they activate the MC4R, suppressing appetite and inhibiting food intake. The effects of nicotine on appetite are also attributed to complex effects on peptides that regulate food intake and body weight. Nicotine also increases energy expenditure by sympathomimetic actions and through the regulation of brain metabolism. Finally, nicotine increases thermogenesis and lipolysis and stimulates the expression of UCP1 in adipose tissue, resulting in a rise in basal metabolism [32]. nAChRs: Nicotinic acetylcholine receptors; POMC: Pro-opiomelanocortin; MC4R: melanocortin-4 receptors; UCP1: Uncoupling protein 1.