Radioautographic study of 125I-VIP binding sites in esophageal muscle layer : comparison with those in rat esophagus and forestomach

Vasoactive intestinal peptide-like immunoreactivity has been demonstrated throughout the gastrointestinal tract in many species, and recently it has been suggested that the lack of an inhibitory effect of VIP in the lower esophageal sphincter is responsible for the pathogenesis of esophageal achalasia. In the present study, the specific binding of VIP on esophageal tissue from achalasia patients and control subjects, rat esophagus and forestomach were studied by radioautographic methods. In the rat forestomach, they were primarily seen on the muscularis mucosae, the circular smooth muscle cells and the vascular smooth muscle cells in the submucosal layer, while few grains were observed on the striated muscle cells in the rat esophagus