Production of endothelium-derived relaxing factor (EDRF) is compromised after ischemia and reperfusion.

Rabbit hind limbs were subjected to 5 hours of ischemia with or without 1 hour of in vivo reperfusion, and the response of femoral artery segments to vasocontrictors and vasodilators was studied in vitro. The ability of endothelium-derived relaxing factor (EDRF)-dependent vasodilators to relax arterial segments was not altered after up to 5 hours of ischemia alone but was significantly decreased after 4 hours of ischemia if followed by 1 hour of in vivo reperfusion. Thus, we concluded that a specific injury occurs to endothelial cells after ischemia-reperfusion, which occurs solely during the reperfusion period.