Release of inflammatory mediators into the gastric wall of rats with acute acetic acid induced ulcer.

An acute, acetic acid induced gastric ulcer in rats is associated with increased capillary permeability and albumin leakage into the gastric wall surrounding the ulcer. This is an inflammatory reaction, and the present experiment was undertaken in an attempt to identify inflammatory mediators in the gastric wall around the ulcer. Rats were pretreated with inflammatory antagonists, and the protein leakage was estimated by means of 125I-labelled albumin 40--60 min and 4 h after ulcer induction. We found no effect on the protein leakage of mepyramine (antihistamine) deseril (antiserotonin) or indomethacin (antiprostaglandin) given separately, or of the combination of mepyramine and deseril. The combination of all three substances, mepyramine, deseril and indomethacin significantly decreased protein leakage at 4 h after ulcer induction. This indicates that prostaglandins are released in the tissues near the acute ulcer. Cimetidine (histamine-H2-antagonist) did not decrease the protein leakage either alone or in combination with mepyramine (histamine-H1-antagonist).