Endoplasmic reticulum stress (ERS) can initiate inflammation, and the coupling of these responses is thought to be fundamental to the pathogenesis of cardiovascular disease. However, the mechanism linking ERS and inflammation in myocardial ischemia/reperfusion needs further investigation. Cultured cardiomyocytes were pretreated with SP600125 or salubrinal, followed by tunicamycin to clarify the involvement of the IRE1α and PERK pathways in ERS inflammation. The cardiomyocytes were given hypoxia/reoxygenation (H/R), and the effects of the NF-κB inhibitor, SN50, were followed. GRP78 protein levels were similar in the tunicamycin (Tm), salubrinal, and SP600125 groups, but were lower in cells treated with SN50. SN50 might effectively block the H/R-induced link between ERS and inflammation in cardiomyocytes by decreasing GRP78. This knowledge will aid in the development of therapies for myocardial ischemia/reperfusion injury.