The present study was designed to investigate the nature of the 5-HT4 receptors affecting the peristaltic reflex in the isolated rat distal colon. A single peristaltic reflex was evoked by infusing Tyrode solution into the lumen of the isolated segment using our modified Trendelenburg's method under an isovolumic condition. A 5-HT4 receptor agonist, mosapride (10 nM), did not affect the threshold pressure and the propagation distance of the reflex contraction, but significantly increased the developed pressure (maximum pressure - threshold pressure) from 19.1 +/- 11.8 cm H2O in the control to 26.8 +/- 13.0 cm H2O (n = 8, P<0.05) without affecting the resting muscle tone in the distal colon. The present result suggests that stimulation of 5-HT4 receptor enhances the propulsive power to move the luminal contents in the rat distal colon.
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http://dx.doi.org/10.1016/s1566-0702(02)00063-2 | DOI Listing |
J Physiol
December 2024
Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA.
The peristaltic reflex has been a central concept in gastrointestinal motility; however, evidence was published recently suggesting that post-stimulus responses that follow inhibitory neural responses provide the main propulsive force in colonic motility. This new concept was based on experiments on proximal colon where enteric inhibitory neural inputs are mainly nitrergic. However, the nature of inhibitory neural inputs changes from proximal to distal colon where purinergic inhibitory regulation dominates.
View Article and Find Full Text PDFJ Neurogastroenterol Motil
October 2024
Dysphagia Research Laboratory, Division of Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA.
Semin Neurol
August 2023
Division of Gastroenterology and Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota.
Propulsion of contents in the gastrointestinal tract requires coordinated functions of the extrinsic nerves to the gut from the brain and spinal cord, as well as the neuromuscular apparatus within the gut. The latter includes excitatory and inhibitory neurons, pacemaker cells such as the interstitial cells of Cajal and fibroblast-like cells, and smooth muscle cells. Coordination between these extrinsic and enteric neurons results in propulsive functions which include peristaltic reflexes, migrating motor complexes in the small intestine which serve as the housekeeper propelling to the colon the residual content after digestion, and mass movements in the colon which lead to defecation.
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