Nicotine is commonly believed to be the primary addictive substance in tobacco smoking. Nicotine exerts its pharmacological effects on the central nervous system by binding to nicotinic acetylcholine receptors (Leonard and Bertrand 2001), and increases dopamine levels in the nucleus accumbens (Pontieri et al. 1996). Despite continued campaigns against cigarette smoking, it remains a leading preventable cause of death in the USA and globally. It has been estimated that one in every five deaths is attributable to cigarette smoking (Peto et al. 1992), resulting in 438,000 deaths and $157.7 billion in healthcare and related expenditures annually in the US (Leistikow 2000; Mokdad et al. 2004).
