NPY and infarction: In vitro studies of isolated cardiomyocytes have shown that NPY has variable and transient effects, including stimulating hypertrophy in cardiomyocytes [125], and can act as a powerful vasoconstrictor that enhances the vasoconstrictive effects of norepinephrine, causing increased blood pressure, local vascular stenosis, and heart spasm, which may eventually lead to myocardial ischemia and infarction.