- Gastrocolic reflex
The gastrocolic reflex or gastrocolic response is one of a number of physiological reflexes controlling the
motility , orperistalsis , of thegastrointestinal tract . It involves an increase in motility of the colon in response to stretch in thestomach and byproducts of digestion in thesmall intestine . The small intestine also shows a similar motility response.The reflex was demonstrated by myoelectric recordings in the colons of animals and humans, which showed an increase in electrical activity within as little as 15 minutes after eating. The recordings also demonstrated that the gastrocolic reflex is uneven in its distribution throughout the colon. The
sigmoid colon is more greatly affected than the right side of the colon in terms of a phasic response; however, the tonic response across the colon is uncertain. When pressure within the rectum becomes increased, the gastrocolic reflex acts as a stimulus for defecation. A number ofneuropeptides have been proposed as mediators of the gastrocolic reflex. These includeserotonin ,neurotensin ,cholecystokinin (CCK), andgastrin .Clinically, the gastrocolic reflex has been implicated in pathogenesis of
irritable bowel syndrome . Also, the serotonin (5HT3) antagonistondansetron decreases the tonic response to stretch.External links
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