Platelet activating factor induced gastric damage in rats: participation of increased gastric vascular permeability.

Pharmacological factors involved in the injurious effect of platelet activating factor (PAF) on the gastric mucosa were studied in the acid (0.15 N HCI)-perfused stomachs of anesthetized rats. PAF infusion (100 ng/kg/min for 20 min, i.v.) induced distinct bleeding in the acid perfusate in proportion to mucosal lesions. Preceding the bleeding, a remarkable increase in mucosal vascular permeability was observed on dye-leakage assessment. Inhibition of the gastric bleeding and the dye leakage was achieved by pretreatment of the animals with CV-3988, a PAF antagonist, and hydrocortisone acetate, in contrast to the aggravation by caffeic acid. These results suggested the importance of mucosal vascular permeability in PAF-induced gastric mucosal lesions.