الفهرس 
Regulation of gastrointestinal tract functionsOnly 14 pages are availabe for public view
 |  | from | 252 |  |  |
| | | from | 252 | | |
Abstract
The function of the GI tract is not only to ensure the metabolic survival of the body but also to sort the ingested food in terms of its nutritive, toxic and pathogenic properties. These tasks are under multiple control systems among which neurons are particularly important and therefore the alimentary canal is equipped with the largest collection of neurons outside the CNS. Many of the transmitters and its receptors present in the brain have also been localized to the ENS and it is not surprising how many brain neurotransmitters are also in the gut, but it sure is interesting how many gut neurotransmitters are in the brain. These neurotransmitters which facilitate communication between muscles, secretory epithelial cells, endocrine cells, and the vasculature of the GI tract, playing a key role in normal GI tract functioning and in the communication between ENS and CNS forming brain-gut axis. More than 25 candidate neurotransmitters have been identified in the ENS, besides the classical neurotransmitters, acetylcholine, adrenaline and noradrenaline, nerve cells in GI tract can express a number of other non-adrenergic non cholinergic putative transmitters. Although, a majority of these NANC substances are neuropeptides, but also amines such as serotonin and dopamine, amino acids like GABA and glutamate, small gaseous molecules such as nitric oxide, carbon monoxide, hydrogen sulfide are considered as NANC transmitters in the ENS. Neuropeptides were earlier grouped together in families according to sequence similarities and currently, the grouping of the neuropeptides involve gene analyses where peptide which originate from the same gene belong the same family and there are several well-investigated families such as opioids, galanin tachykinins , bombasin and the VIP-family. These neuropeptides show a wider but less dominant effect throughout the bowel, and inspite of fact that their action is not as dominant as of the classical neurotransmitters, they play a significant role in GI tract functions and there implications in GI tract extend beyond gastroenterology, as multiple disorders of the GI tract are now thought to be related to alterations in gut brain communication or changes in the brain-gut axis. Neurotransmitters are also implicated in one of the most debilitating functional gut disorders, irritable bowel syndrome (IBS), which manifested by abdominal pain, cramping, bloating, constipation or diarrhea and in some patients alternating diarrhea and constipation. Because of neurotransmitters are participate in pathophysiology of IBS, so it can be used as a line of management of the most common type of FGID.