CORRELATION BETWEEN TRANSMUCOSAL POTENTIAL DIFFERENCE AND MORPHOLOGICAL DAMAGE DURING ASPIRIN INJURY OF GASTRIC-MUCOSA IN RATS

The potential difference (PD) that is maintained across healthy gastri c mucosa is thought to be due to asymmetric ion pumping combined with resistance to back-diffusion of the separated charge. However, the str uctures that are responsible for this have not been clearly defined. T his study examined the temporal changes in PD in rat stomach after inj ury by a single dose of aspirin. Multiple linear regression was used t o compare this with the time course of several parameters of histologi cal damage: (i) the per cent mucosal length showing superficial (confi ned to surface and gastric pits), deep (involving the isthmus or deepe r in oxyntic glands) and total damage; (ii) the number of discrete ero sions; and (iii) the total area of erosions per cm sectioned. Mucosal PD fell during the first 30-60 min after aspirin. Superficial damage a ppeared early and was already recovering by this time. The time course of deep damage more closely matched the alterations in PD and stepwis e regression analysis showed that this could be predicted by the amoun t of deep damage alone (P < 0.001). Changes in transmucosal PD after a cute aspirin injury probably reflect damage to structures in the oxynt ic glands and not just the breaking of the surface and pit cell 'barri er'.