Competition assays were performed in adult rat brain cortex homogenates labeled with 150pM [3H]EB. Binding of A-84543 (◆), H-11ONM (*), (●) H-11MNH, (+) H-11ONH and H-11PNH (X), were compared to that of A-85380 (■), a high affinity nAChR agonist, DHβE (▲) a high affinity nAChR antagonist, and Nicotine (▼). The data were analyzed by nonlinear least square regression method using GraphPad Prism 5 software (GraphPad Software Inc. San Diego, CA). IC50 and Ki values are presented in Table II. The data shown is representative of n = 3–6 independent experiments using triplicates.