In mammals, combinations of nAChR subunits from subfamilies II (α7) and III (α2–α6, β2–β4) result in the formation of functional hetero- and homo- pentamers (Le Novère et al., 2002). In striatal DA terminals, heteropentamers display two α/β pairs in the form of α4/β2 and/ or α6/β2 and/or α4/β4 (Champtiaux et al., 2003). Nicotinic control of striatal DA release depends on β2 subunit-containing nAChRs (Zhou et al., 2001; Exley et al., 2012). To verify the role of β2-containing receptors in the augmentation of accumbal DA release by selective activation of CINs, we examined the effect of the β2-containing nAChR antagonist dihydro-β-erythroidine (DHβE). Application of DHβE (1 μM) resulted in a potent reduction of DA peak levels elicited by optical stimulation (by 89.05 % relative to pretreatment values; p < 0.0001; n=4) (Fig. 3B).
