TABLE 1.

Summary of neuronal nAChR subunit expression in reward circuitry of adult rodents.

Subunit	Expression profile	Notable properties	References
α2	IPN		Gotti et al., 2009
α3	Basolateral amygdala, HPC, hypothalamus, MHb, thalamus, VTA		Wada et al., 1989; Champtiaux et al., 2002
α4	Widespread	High affinity, upregulated by chronic nicotine	Wada et al., 1989; Flores et al., 1992
α5	Caudate putamen, MHb, SNc, VTA	Does not participate in ACh binding	Wada et al., 1990; Exley et al., 2012
α6	Locus coeruleus, SNc, VTA	Downregulated by chronic nicotine	Le Novere, 1996; Lai et al., 2005
α7	Amygdala, HPC, hypothalamus, VTA	High Ca2+ permeability, rapid desensitization, forms homopentamers	Seguela et al., 1993
β2	Widespread	High affinity, upregulated by chronic nicotine	Wada et al., 1989; Flores et al., 1992
β3	LHb, MHb, SNc, VTA	Does not participate in ACh binding	Deneris et al., 1989
β4	IPN, MHb		Quick et al., 1999; Millar and Gotti, 2009

HPC, hippocampus; IPN, interpeduncular nucleus; LHb, lateral habenula; MHb, medial habenula; SNc, substantia nigra pars compacta; VTA, ventral tegmental area.