[Afferent nerve endings in the small intestine and the stomach. Light and electron microscopic studies].

1. In the mucous membrane of the duodenum and pylorus there have been identified free club- and tree like endings by ligth and electron microscopy. These endings lie flat between the muscularis mucosae and the glandular basis. 2. In the duodenum of the dog the receptors are undoubtly formed by myelinated axons. 3. According to neurophysiological results these free afferent endings are similar to PAINTAL'S (1957, 1963) mucosal mechanoreceptors.