The effects of the stable thromboxane A2-mimetic, U46619, on gastric mucosal damage and gastric non-parietal secretion in the rat.

The effects of the thromboxane A2-mimetic, U46619, and the thromboxane receptor antagonist, AH23848, on ethanol-induced gastric mucosal damage and gastric non-parietal secretion have been examined in the rat. Oral dosing with U46619 or AH23848 produced a dose-related inhibition of ethanol-induced gastric mucosal damage in the conscious rat, and these effects were partially blocked by indomethacin treatment. Intragastric application of U46619 or AH23848 to the stomach of the anaesthetized rat stimulated the gastric secretion of a juice which consisted principally of Na+ and Cl- ions. These secretagogue effects of both compounds were blocked by indomethacin treatment. These results show that U46619 and AH23848 induce secretory and protective effects in the stomach of the rat, although these responses probably do not involve thromboxane receptors and are mediated, at least in part, by endogenous prostaglandins. The results are discussed in relation to the role of endogenous thromboxane A2 in gastric mucosal protection, and of the possible protective function of non-parietal secretion in the stomach.