nAChRs are involved in the presynaptic control of DA release in the striatum (Hersch et al., 1994; Marshall et al., 2002; Rapier et al., 1990; Wonnacott et al., 2000). To confirm that CIN-driven enhancement of DA release is mediated by activation of nAChRs, we monitored DA levels while performing selective optical activation of CINs in the absence and presence of nAChR antagonists. Mecamylamine (n=6) decreased CIN stimulation-induced DA release with a half maximal inhibitory concentration (IC50) of 0.61 μM (Fig. 3A). The highest dose used (20 μM) decreased DA levels by 85.8 ± 3 % compared to pre-drug conditions.
