Transmural electrical potential difference in the mammalian esophagus in vivo

A simple, safe, accurate, and reproducible technique for measuring the transmural electrical potential difference (PD) of the esophagus has been developed. This technique, a modification of those previously used, allows simultaneous correlation of the PD profile with the pressure profile obtained during routine manometry. With this technique, a subcutaneous reference bridge was shown to detect accurately a lumennegative electrical orientation for the esophageal PD in three species: rabbit, opossum, and man. A characteristic and reproducible PD profile was present for each species. In the rabbit the gastric PD was low, -12 mv, relative to the body of the esophagus, -26 to -29 mv. In contrast, both opossum and man had relatively high gastric PD's (-36 to -43 mv) when compared to esophageal PD's (-12 to -25 mv). In the rabbit and opossum, the PD in the lower esophageal sphincter (-5 to -6 mv) was less than both gastric or esophageal PD's, whereas in human beings the lower esophageal sphincter PD (-22 mv) was between gastric and esophageal values. In vitro PD measurements and histological studies of opossum esophagus revealed differences in the epithelium which correlated with the different in vivo PD's.