Fig. 1. Blockade and activation of neuronal nAChRs. (  A  )  ACh-evoked currents recorded in α4β2, α3β4, α3β4α5, and α7 receptors expressing oocytes in control conditions (left ), during atracurium exposure (middle ), and after recovery (right ). Dashed lines indicate the atracurium application time, whereas bars indicate the ACh application. (B, Left  )  Activation of the α4β2 and α3β4 neuronal nicotinic acetylcholine receptors (nAChRs) by low concentrations of ACh, atracurium, or laudanosine. (Right ) Plots on a log–log scale ACh- (squares), atracurium- (triangles), and laudanosine (circles)–evoked currents.