Figure 2: Feedforward metabolic vasodilation mediated by -derived H2O2. Increased rate and strength of myocyte contraction increase mitochondrial metabolism and flux through the electron transport chain (ETC), driving greater production of , which is converted to H2O2 by manganese superoxide dismutase (MnSOD). H2O2 diffuses to the vascular smooth muscle of coronary resistance vessels, activating channels and resulting in membrane hyperpolarization and vasodilation.