[Role of protons and bicarbonate in adaptative gastric cytoprotection].

The unknown mechanism of adaptative gastric cytoprotection (AGC) induced by 20% ethanol and subsequent injury with 70% ethanol was studied in wistar rats. Pretreatment with indomethacin or HgII2 did not prevent the AGC, there suggesting that neither endogenous PGS nor gastric mucus take part in its mechanism. On the other hand, ranitidine pretreatment blocked and even aggravated the damage induced by ethanol-ethanol. In contrast, the latter phenomenon was reverted by 20% acidified ethanol. It is concluded that a back diffusion of H+ and bicarbonate play important roles in the AGC mechanism.