New treatments are being discovered for smoking cessation, and the Food and Drug Administration has recently approved varenicline, which is a partial nAChR agonist and antagonist. The agonist effect is caused by binding to nicotinic receptors and stimulating receptor-mediated activity. The antagonist effect occurs when varenicline blocks the ability of nicotine to activate nicotinic receptors. Imaging studies with varenicline may tell us more about nicotine dependence and the role of the α4β2 nicotine receptor.
