Transgenic mice with cardiac-specific MR overexpression show prolonged ventricular repolarization and severe arrhythmia associated with a decrease of outward potassium current (38) and abnormal Ca2+ release from the sarcoplasmic reticulum during diastole with consequent generation of cardiac arrhythmias (37). The gene discussed is NR3C2; the disease is chronic obstructive pulmonary disease.