For example, infusion of vasoactive intestinal peptide increased the concentration of myocardial vasoactive intestinal peptide and reversed existing myocardial fibrosis in rats311, and cyclopeptide RD808 neutralized the β1-adrenergic receptor, thus attenuating myocardial injury induced by the β1-adrenergic receptor in mice312. Here, VIP is linked to Myocardial fibrosis.