Roles of three distinct neurogenic motor patterns during pellet propulsion in guinea-pig distal colon.

Autor: Costa M; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Keightley LJ; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Wiklendt L; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Hibberd TJ; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Arkwright JW; College of Science and Engineering, Flinders University, Adelaide, SA, Australia., Omari T; Discipline of Surgery and Gastroenterology, Flinders Medical Centre, Adelaide, SA, Australia., Wattchow DA; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia.; Discipline of Surgery and Gastroenterology, Flinders Medical Centre, Adelaide, SA, Australia., Zagorodnyuk V; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Brookes SJH; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia., Dinning PG; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia.; Discipline of Surgery and Gastroenterology, Flinders Medical Centre, Adelaide, SA, Australia., Spencer NJ; College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Discipline of Human Physiology, Adelaide, SA, Australia.
Jazyk: angličtina
Zdroj: The Journal of physiology [J Physiol] 2019 Oct; Vol. 597 (20), pp. 5125-5140. Date of Electronic Publication: 2019 Oct 01.
DOI: 10.1113/JP278284
Abstrakt: Key Points: Enteric neural circuits enable isolated preparations of guinea-pig distal colon to propel solid and fluid contents by a self-sustaining neuromechanical loop process. In addition there are at least three neural mechanisms which are not directly involved in propulsion: cyclic motor complexes, transient neural events and distal colon migrating motor complexes. In excised guinea-pig colon we simultaneously recorded high resolution manometry, video-imaging of colonic wall movements and electrophysiological recordings from smooth muscle, which enabled us to identify mechanisms that underlie the propulsion of colonic content. The results show that the intermittent propulsion during emptying of the multiple natural faecal pellets is due to the intermittent activation of cyclic motor complexes and this is facilitated by transient neural events. Loss or dysfunction of these activities is likely to underlie disordered gastrointestinal transit.
Abstract: It is well known that there are different patterns of electrical activity in smooth muscle cells along different regions of the gastrointestinal tract. These different patterns can be generated by myogenic and/or neurogenic mechanisms. However, what patterns of electrical activity underlie the propulsion of natural faecal content remains unknown, particularly along the large intestine, where large quantities of water are reabsorbed and semi-solid faeces form. In this study, we developed a novel approach which enables for the first time the simultaneous recording of high resolution intraluminal manometry, electrophysiology from the smooth muscle, and spatio-temporal video imaging of colonic wall movements. Using this approach we were able to reveal the nature of enteric neuromuscular transmission and patterns of motor activity responsible for the movement of content. Three distinct neurogenic patterns of electrical activity were recorded even in the absence of propulsive movement. These were the cyclic motor complexes (CMCs), the transient neural events (TNEs) and the slowly propagating distal colonic migrating motor complexes (DCMMCs). We present evidence that the initiation of pellet propulsion is due to a cyclic motor complex (CMC) occurring oral to the pellet. Furthermore, we discovered that the intermittent propulsion of natural faecal pellets is generated by intermittent activation of CMCs; and this propulsion is facilitated by hexamethonium-sensitive TNEs. However, TNEs were not required for propulsion. The findings reveal the patterns of electrical activity that underlie propulsion of natural colonic content and demonstrate that propulsion is generated by a complex interplay between distinct enteric neural circuits.
(© 2019 The Authors. The Journal of Physiology © 2019 The Physiological Society.)
Databáze: MEDLINE
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