Studies have shown that activation of κ-OR can improve the activity of NOS under hypoxia conditions and then upregulate NO levels [14], dilate the abdominal aortic ring of rats in a time-dose-dependent manner [15], and inhibit inflammation and cardiomyocyte apoptosis caused by myocardial ischemia [16]. Here, OPRK1 is linked to myocardial ischemia.