Fig. 1. Representative tracings of current responses of hnAChRs before (left ), during (middle ), and after (right ) perfusion of 30 μM ketamine. The current responses of the α³β⁴, α⁴β², and α⁴β⁴channels were evoked by EC^30–60(agonist concentration giving 30–60% of the maximal response) concentrations of acetylcholine (100, 3, and 30 μM for the α³β⁴, α⁴β², and α⁴β⁴channels, respectively). Inward current is downward. The period of treatment with drugs is indicated by bars.