On the basis that the reactive oxygen species (ROS), such as the superoxide anion and H2O2, mediate the cytotoxicity of dopaminergic neurons by 6-OHDA [99] and EAG1 channels are greatly sensitive to H2O2 modification [31], it will be worth exploring the physiological roles of EAG1 channels in dopaminergic midbrain neurons as well as in Parkinson's disease. The gene discussed is KCNH1; the disease is Parkinson disease.