associated with nicotine dependence and smoking behavior in several European-ancestry samples (Bierut et al., 2007, Ehringer et al., In press, Hoft et al., 2009, Saccone et al., 2009a, Saccone et al., 2007, Zeiger et al., 2008), though the biological implications are still largely unclear. Interestingly, β3 knock-out mice show significantly reduced α6 expression in the brain resulting in deviated receptor targeting activity (Gotti et al., 2005). The α6 subunit is also known to occur in nicotinic receptor subtypes that modulate the dopamine reward pathway in mice (Klink et al., 2001).
