Extensive research also has examined the neuronal nicotinic acetylcholine receptors (nAChRs), which are affected by both nicotine and alcohol. DNA variation in the genes that encode the subunits of these receptors may play a role in the susceptibility to alcohol dependence and nicotine addiction. Similar to the GABA-A receptors, the genes encoding these receptors are found in clusters on several chromosomes. Studies have reported an association of SNPs in CHRNA5–CHRNA3 (Wang et al. 2009) and CHRNA6–CHRNB3 (Hoft et al. 2009) gene clusters with alcohol dependence or alcohol consumption.
