Neurohumoral control of esophageal epithelial electrolyte transport

The neurohumoral control of epithelial esophageal electrolyte transport was investigated by studying the effect of various hormones and neuroeffector agents on the potential difference (PD) in vivo or on the electrical parameters of electrolyte transport in vitro. The rabbit esophagus, which has no submucosal esophageal glands, demonstrated no effect of pentagastrin, cholecystokinin octapeptide, or synthetic secretin in vivo, and no effect of these hormones or of vasopressin, aldosterone, carbachol, epinephrine, or cAMP in vitro. The rabbit esophagus did respond to metabolic substrates (glucose) in vitro by increasing sodium absorption. In contrast, the opossum esophagus, which contains extensive submucosal glands, had a lower electrical resistance, PD, short-circuit current, and sodium absorption with higher chloride secretion. This esophagus responded to carbachol and epinephrine by sodium and chloride secretion. We believe that only the submucosal glands of the esophagus are under significant neurohumoral control while the sodium transporting function of the stratified squamous epithelium of this organ is important in maintaining its barrier function.