GASTRIC TRANSMUCOSAL POTENTIAL DIFFERENCE - EFFECT OF ANTISECRETORY AND GASTROPROTECTIVE DRUGS

1. Ion transport and electrical resistance of the gastric mucosa are r esponsible for the generation of the transmucosal potential difference (PD), which is considered an index of mucosal integrity. 2. The aim o f the present work was to study the effect of some antisecretory and g astroprotective agents on PD in stomachs damaged by ethanol. 3. Contro l PD values measured in anesthetized rats were 35 to 40 mV (mucosa neg ative). Oral administration of 96% ethanol or intragastric instillatio n of 20% ethanol induced an abrupt fall in PD from the basal values of 40.4+/-1.0 mV and 39.6+/-0.1 mV to 14.6+/-2.5 mV and 11.7+/-1.3 mV, r espectively. 4. Oral and/or topical pretreatment with the antisecretor y agents ranitidine and timoprazole, as well as with the gastroprotect ive agents PGE(2) and pentacaine, but not with an aluminum-and magnesi um-containing antacid and with sucralfate, reduced the maximal drop of PD caused by ethanol. 5. After the administration of concentrated eth anol, hemorrhagic lesions were formed in the glandular stomach. 6. Wit h the exception of ranitidine, all the drugs tested prevented the deve lopment of lesions after ethanol administration. 7. The results indica te that the gastric barrier can be protected by various drugs that act through different mechanisms. (C) 1998 Elsevier Science Inc.