Koza Jarosław, Kwiatkowska Renata, Jurgoński Adam, PujanekMałgorzata, Ameryk Monika, Sikorski Piotr, Meder Agnieszka, Świątkowski Maciej. The importance of serotonin in the gastrointestinal tract. Journal of Education, Health and Sport. 2017;7(12):104-110. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.1102699 http://ojs.ukw.edu.pl/index.php/johs/article/view/5109 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 1223 (26.01.2017). 1223 Journal of Education, Health and Sport eISSN 2391-8306 7 © The Authors 2017; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 10.11.2017. Revised: 15.11.2017. Accepted: 12.12.2017. The importance of serotonin in the gastrointestinal tract Jarosław Koza1, Renata Kwiatkowska1, Adam Jurgoński2, Małgorzata Pujanek1, Monika Ameryk1, Piotr Sikorski1, Agnieszka Meder1, Maciej Świątkowski1 1Department of Gastroenterology and Nutrition Disorders, Nicolaus Copernicus University in Toruń, Faculty of Health Sciences, Collegium Medicum in Bydgoszcz, Poland 2Division of Food Science, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland Corresponding author: Jarosław Koza, Department of Gastroenterology and Nutrition Disorders, University Hospital no. 2, Ujejskiego 75 Str, 85-168 Bydgoszcz, Poland; e-mail: jaroslaw.koza@cm.umk.pl SUMMARY Introduction. Serotonin also called as 5-hydroxytryptamine (5-HT) is a very important neurotransmitter in the central nervous system, also plays an important role in the gastrointestinal tract. It is known that the basis of the peristaltic reflex in the gut is the result of serotonin release from enterochromaffin cells. The vast majority of serotonin in the human body is associated with the gastrointestinal tract. It is produced by enterochromaffin cells, the activation of which causes the serotonin secretion into the intercellular space and its active action through the receptors. There are seven main types of serotonin receptors and some of them have also subtypes. Description of the current knowledge and conclusions. Serotonin is responsible for some symptoms of carcinoid syndrome. It is the result of higher 5-hydroxytryptamine content in the body. Moreover disrupted serotonin system is found in different gastrointestinal disorders e.g. in gastroesophageal reflux disease, functional heartburn, hypersensitive esophagus, functional dyspepsia, irritable bowel syndrome (both diarrhoea predominant and constipation predominant) as well as in inflammatory bowel diseases. Knowledge of changed mechanisms in particular diseases facilitates the optimal choice of treatment. Drugs affecting the serotonin system in gastroenterological clinical practice are useful especially in the case of abnormalities in the brain - gut axis. Key words: serotonin, gastrointestinal tract