Gastric mucosal protective action of endothelium-derived relaxing factor.

The change in the endothelial function by the application of 0.6 N HCl and the effects of endothelium-derived relaxing factor (EDRF) inhibitors and nitrites on HCl-induced lesions were studied to clarify the effect of EDRF on gastric lesions in rats. The EDRF-induced increase in the gastric mucosal hemodynamics induced by vagal stimulation or intra-arterial administration of acetylcholine was inhibited by the EDRF inhibitors or removal of endothelial cells. Topical application of 0.6 N HCl on the exposed gastric mucosa abolished the response of the mucosal hemodynamics to acetylcholine or vagal stimulation. Gastric lesions induced by 0.45 N HCl were enhanced by EDRF inhibitors or removal of endothelial cells from gastric submucosal arterioles.