Is calcium a coronary vasoconstrictor in vivo?
Calcium has a coronary vasoconstricting effect and a positive inotropic effect in vivo. This vasoconstricting effect impairs coupling of coronary blood flow to the augmented myocardial oxygen demand by metabolic vascular control mechanisms. Dobutamine is an inotropic agent with no apparent direct action on coronary resistance vessels in vivo.
Increased myocardial ischemia after food is caused by mechanisms other than endothelial dysfunction and by meal components other than cooked fat.