Neuronal nAChRs are heterogeneous cationic channels that are widely distributed in the nervous system and non-neuronal tissues. The subunit composition and biophysical properties of nAChRs depend on the subtype and the area of the brain in which they are found (Gaimarri et al. 2007; Gotti et al. 2007; Zoli et al. 2002). Nicotine diffuses readily into the brain and binds to ligand-gated nAChRs. After nicotine binds to the nAChR, the channel opens and allows entry of cations (Na+, Ca2+).
