Smoking is the leading cause of self-induced morbidity and premature mortality, and 12.8% of the US adult population meets criteria for nicotine dependence (ND; Grant et al. 2004). In the brain, nicotinic acetylcholine receptors (nAChRs) are the primary target for nicotine. nAChRs are ligand-gated ion channels that respond to the endogenous neurotransmitter acetylcholine as well as nicotine (Arias et al. 2006; McGehee 1999).
