Serotonin and the GI tract

Abstract

Serotonin (5-hydroxytryptamine, 5-HT) participates in several functions of the gastrointestinal tract. Receptors in seven families (5-HT(1)-5-HT(7)) were identified, many of which are present on enterocytes, intrinsic and extrinsic neurons, interstitial cells, and gut myocytes. Most 5-HT is released from enterochromaffin cells in response to physiologic and pathologic stimuli. Roles of 5-HT in health include control of normal gut motor activity, secretion, and sensation, and regulation of food intake and cell growth. Abnormalities of serotonergic function contribute to symptom genesis in functional bowel disorders, inflammatory and infectious diseases of the gut, emetic responses to varied stimuli, obesity, and dysregulation of cell growth. Therapies acting as agonists or antagonists of 5-HT receptors or that modulate 5-HT reuptake play prominent roles in managing these conditions, although use of many agents is hampered by cardiopulmonary complications. Novel agents are in testing, which may exhibit efficacy without significant toxicity.

Granisetron Transdermal System for Treatment of Symptoms of Gastroparesis: A Prescription Registry Study

“…11,12 Perception of gut stimulation is also mediated by serotonergic (5-HT) receptors on intrinsic nerves and extrinsic sensory pathways that project to the nodose and dorsal root ganglia. 13 5-HT 3 mechanisms are involved in vomiting in a range of emetic stimulation; this has been primarily studied in chemotherapy-induced nausea and vomiting. 5-HT 3 receptors are on vagal afferent nerves projecting to the brainstem, as well as to the area postrema, nucleus tractus solitarius, and dorsal motor nucleus of the vagus, and may activate during emetic stimulation.…”

“…5-HT 3 receptors are on vagal afferent nerves projecting to the brainstem, as well as to the area postrema, nucleus tractus solitarius, and dorsal motor nucleus of the vagus, and may activate during emetic stimulation. 13 Thus, there are 5-HT 3 receptors mediating pathways which transmit perception of nausea and vomiting from the gastrointestinal track. Interestingly, this study in patients with symptomatic refractory gastroparesis demonstrated that there were improvements not only in nausea and vomiting, but also in other associated symptoms of gastroparesis including postprandial fullness, loss of appetite, upper abdominal pain, and early satiety.…”

Food restriction beginning at lactation interferes with the cellular dynamics of the mucosa and colonic myenteric innervation in adult rats

“…Despite the proven existence of 5-HT receptors in intestinal smooth muscles (Hasler 2009) and in contrast to the increase in the muscularis mucosae thickness, we can exclude the possibility that the colonic external muscle atrophy observed in FR animals is modulated by the secretion of 5-HT in enteroendocrine cells because the receptors in this intestinal tunica play an important role in peristalsis. They contribute to circular muscle relaxation by acting as a target for endogenous 5-HT secreted by both neuronal and enteroendocrine cells (Tonini et al 2005).…”

“…It regulates the growth of various tissues, including smooth muscle cells, fibroblasts, nerves, and epithelial cells in intestinal crypts (Hasler 2009). The presence of 5-HT receptors in enterocytes (Hasler 2009) suggests that the longer crypts observed in the FR group could be related to the stimulation of enteroendocrine cells, which were significantly increased and are known to generate hyperplastic crypts (Spiller 2007).…”

Avaliação dos efeitos de 5-hidroxitriptofano em-hidroxibenzilhidrazine associados a Lactobacillus spp. na morfometria intestinal e imunomarcação de serotonina em frangos de corte desafiados com Salmonella Enteridis

“…Sua liberação para o lúmen ou lâmina própria faz com que atue sobre células entéricas do sistema nervoso e inicie atividades secretó-rias e crescimento celular de vários tecidos, incluindo vilosidades e criptas intestinais (Fukumoto et al 2003, Hasler 2009, Khan & Ghia 2010.…”