In DM mice, the atrial expression of oxidized CaMKII (oxi-CaMKII) (Figure 5, A and C, 1.35 ± 0.11 oxi-CaMKII/CaMKII in control vs. 2.36 ± 0.38 oxi-CaMKII/CaMKII in DM, P = 0.035) as well as phosphorylated RyR2 (Ser2814) (Figure 5, B and C, 0.72 ± 0.14 p-RyR2 (Ser2814)/RyR2 in control vs. 1.44 ± 0.18 p-RyR2 (Ser2814)/RyR2 in DM, P = 0.013) were increased when compared with those of the control mice. The gene discussed is RYR2; the disease is diabetes mellitus.