NRG-1 inhibits cardiomyocyte ER stress induced by tunicamycin and dithiothreitol. NRG-1 inhibits cardiomyocyte ER stress through ErbB4 receptor. The inhibitory effects of NRG-1 on cardiomyocyte ER stress is through PI3K/Akt signaling pathway. NRG-1 attenuates apoptosis and ER stress induced by H/R in cardiomyocytes. NRG-1 reduces the myocardial I/R injury and ER stress in I/R heart.