[Methodologic aspects of measuring the potential differences in the gastrointestinal tract: effect of electrode placement and electrolyte concentration of the measuring electrode on the magnitude of the transepithelial potential difference].

The transepithelial electric potential difference (tPD) of the colonic mucosa was investigated in children in-vivo. The potential difference was measured by so-called "flowing"-electrodes. The current paper presents methodical considerations, for instance electrolyte concentration of the luminal electrode and position of the serosal electrode (reference-electrode), and their influence on the tPD-measurement.