Is there an abluminal release of endothelium-derived relaxing factor (EDRF)?

In superfusion bioassay systems of rabbit thoracic aorta and femoral artery ring segments as well as canine femoral artery and coronary ring segments the release of endothelium-derived relaxing factor (EDRF) was stimulated by acetylcholine in donor segments with intact endothelium. The transition of EDRF through the vessel wall ("abluminal release") was not revealed in both bioassay systems. Externally applied acetylcholine did not reach the luminal surface of rabbit thoracic aorta but induced EDRF release in canine femoral artery segments.