Chromatographic elution of imipramine from the CMAC-hα4β2 AChR column. (A) Imipramine is eluted from the column with ammonium acetate buffer (10 mM, pH 7.4) and 15% methanol as the mobile phase, at 0.2 mL/min and 20 °C. The dashed line represents the elution of imipramine from the CMAC-hα4β2 AChR column in the presence of κ-BTx (the immobilized AChR is mainly in the resting state), and the straight line represents the elution of imipramine from the CMAC-hα4β2 AChR column in the presence of (±)-epibatidine (the immobilized AChR is mainly in the desensitized state). (B) Imipramine is eluted from the CMAC-hα4β2 AChR column with (±)-epibatidine present in the mobile phase (predominantly desensitized state) at different temperatures (from right to left: 10, 12, 16, 20, and 25 °C).