Gastric potential difference as a model in clinical pharmacology: assessment of gastric mucosal response to aspirin.

Gastric potential difference in 16 healthy subjects (GPD) was measured on three different days to assess baseline variability. The effect of three different doses of aspirin on PD in 19 additional subjects was determined. Several new parameters are suggested for better description of the GPD changes following ingestion of known gastric irritants. From these parameters, a Reiz Index (RI) was calculated as a single term representing the extent and severity of the GPD response to aspirin. One-way Anova followed by Scheffe comparisons showed significant differences between the mean RI values resulting from the administration of aspirin 250, 500 and 1000 mg.