Chromostatin is a peptide fragment representing chromogranin A (124-143). Chromostatin exhibits cardiomodulatory activity, inhibiting vasoconstriction in thoracic arteries and saphenous veins induced by K+, norepinephrine, and endothelin-1. Additionally, chromostatin inhibits catecholamine secretion in chromaffin cells through the activation of protein phosphatase 2A (PP2A).