κ-Opioid receptor stimulation modulates TLR4/NF-κB signaling in the rat heart subjected to ischemia-reperfusion

► U50,488H modulates TLR4/NF-κB signaling in the rat heart subjected to MI/R. ► U50,488H decreased NF-κB expression in the ischemia and risking area of MI/R. ► U50,488H down-regulated TLR4 gene and protein expressions in the MI/R heart. ► U50,488H inhibited TNF-a levels in the serum and MI/R tissue. ► U50,488H inhibited neutrophil infiltration in the heart subjected to MI/R.