Figure 2.

Scheme about the effect of reactive oxygen species (ROS) in cardiac tissue at different levels. Also, the potential role of melatonin as an antioxidant molecule and its implications for arrhythmia prevention are illustrated (CaMKII: Ca²⁺/calmodulin-dependent kinase II; SERCA: sarco/endoplasmic reticulum Ca²⁺-ATPase; ROS: reactive oxygen species; ICa: calcium current; INa: sodium current; KATP: ATP-sensitive potassium channel; NCX: sodium-calcium exchanger; ETC: electron transport chain; NOS: nitric oxide synthases; NADPH: nicotinamide adenine dinucleotide phosphate hydrogen).