[Oral and gastric diffuse neuroendocrine system: discussion questions of structure and function]

Abstract

In recent years, diffuse neuroendocrine system (DNES) in the digestive tract attracted worldwide attention. Cells throughout the digestive tract receive information in many forms, including chemical messengers that emanate from other cells. At the turn of XIX century, the concept of nervism or entire neural control of digestive functions, developed by Pavlov prevailed. The prototype for chemical communication came with discovery of the first hormone, secretin and histamine, a non-nervous and non-gastrin compound by L. Popielski from Lviv university. This review presents past and present advances in physiological mechanisms underlying digestion and newly recognized several groups of hormones and transmitters, that produced by digestive diffuse neuroendocrine system cells. Two-way communication pathways operate between the brain and the gut, each comprising afferent fibers signaling sensory information from the gut to the brain and efferent fibers transmitting signals in opposite direction. Short intramural and long extramural reflexes are triggered as well as various gut hormones are released by feeding that "cooperate" with the "brain-gut axis" in alteration of the digestive exocrine and endocrine secretion, motility and blood circulation and feeding behavior. Up till now, researches about gastric DNES in human and animal have been reported, but the research data about representation DNES in oral cavity are scarce. In the present paper, described ultrastructure of oral endocrinocytes from rat gum mucous by electron-microscopic analysis method. Their morphological feature provides evidence of neuroendocrine acting mode. This research can morphologically prove that the oral DNES cells is almost the same as of stomach and gut. It shows morphological evidence of representation brain -gut axis in oral cavity with an neuroendocrine-exocrine mode of peptide action. It suggests that the oral DNES play important role in the diversity of physiological functions, mucosal repair and reconstitutional process and homeostasis in oral cavity. Future investigation of oral DNES has opened new therapeutic approaches to various mucous injury-related diseases.