MAOA and Alzheimer disease: HT-22 cells treated with the AD-related Aβ(1–40) peptide (30 μM; 48 h) had significantly more free Ca2+ (Fig. 5A, top panels) and a corresponding increase in ROS production (Fig. 5A, middle panels) that was decreased by pretreatment with the MAO-A inhibitor clorgyline (100 μM, 1 h) (Fig. 5A, bottom panels).