Presence of melatonin in the human hepatobiliary-gastrointestinal tract

Messner, M.; Huether, Gerald; Lorf, Thomas; Ramadori, Giuliano; Schwörer, H.

doi:10.1016/s0024-3205(01)01143-2

Cited by 104 publications

(93 citation statements)

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“…However, these levels disappeared when food was restricted. Furthermore, the findings that melatonin levels were higher in the portal vein than in the systemic circulation and that the TRP-induced elevation in the portal vein occurred earlier than in the systemic circulation also demonstrated that GIT contributes significantly to circulating plasma levels of melatonin, especially during the daytime [8,54,59,71,79].…”

Section: Melatonin Synthesis and Secretionmentioning

confidence: 93%

“…Interestingly, whereas the nighttime concentrations peaked at the day 7 of the embryonic development, the daytime levels reached on that day their lowest point [53]. Phylogenetically, melatonin was identified in the GIT of fishes, reptiles, amphibians, birds and mammals, including humans [9,42,43,45,49,52,54].…”

Section: Ontogeny and Phylogenymentioning

confidence: 99%

“…Furthermore, melatonin receptors or binding sites were found in many segments of the GIT of various birds and mammals, including humans [9,52,[64][65][66][67][68]. Although binding site parameters exhibited diurnal variation in some species, this was not confirmed in others [52,54,69]. In addition, large variations of melatonin concentrations in the individual segments of the GIT were found among many species of birds and mammals [9,35,38,44,57,64,66,[68][69][70].…”

Section: Ontogeny and Phylogenymentioning

confidence: 99%

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Localization, Physiological Significance and Possible Clinical Implication of Gastrointestinal Melatonin

2001

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The gastrointestinal tract (GIT) is a major source of extrapineal melatonin. In some animals, tissue concentrations of melatonin in the GIT surpass blood levels by 10–100 times and the digestive tract contributes significantly to melatonin concentrations in the peripheral blood, particularly during the day. Some melatonin found in the GIT may originate from the pineal gland, as the organs of the digestive system contain binding sites, which in some species exhibit circadian variation. Unlike the production of pineal melatonin, which is under the photoperiodic control, release of GI melatonin seems to be related to periodicity of food intake. Melatonin and melatonin binding sites were localized in all GI tissues of mammalian and avian embryos. Postnatally, melatonin was localized in the GIT of newborn mice and rats. Phylogenetically, melatonin and melatonin binding sites were detected in GIT of numerous mammals, birds and lower vertebrates. Melatonin is probably produced in the serotonin-rich enterochromaffin cells (EC) of the GI mucosa and can be released into the portal vein postprandially. In addition, melatonin can act as an autocrine or a paracrine hormone affecting the function of GI epithelium, lymphatic tissues of the immune system and the smooth muscles of the digestive tube. Finally, melatonin may act as a luminal hormone, synchronizing the sequential digestive processes. Higher peripheral and tissue levels of melatonin were observed not only after food intake but also after a long-term food deprivation. Such melatonin release may have a direct effect on the various GI tissues but may also act indirectly via the CNS; such action might be mediated by sympathetic or parasympathetic nerves. Melatonin can protect GI mucosa from ulceration by its antioxidant action, stimulation of the immune system and by fostering microcirculation and epithelial regeneration. Melatonin may reduce the secretion of pepsin and the hydrochloric acid and influence the activity of the myoelectric complexes of the gut via its action in the CNS. Tissue or blood levels of melatonin may serve as a marker of GI lesions or tumors. Clinically, melatonin has a potential for a prevention or treatment of colorectal cancer, ulcerative colitis, irritable bowel syndrome, children colic and diarrhea.

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Section: Melatonin Synthesis and Secretionmentioning

confidence: 93%

Section: Ontogeny and Phylogenymentioning

confidence: 99%

Section: Ontogeny and Phylogenymentioning

confidence: 99%

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Localization, Physiological Significance and Possible Clinical Implication of Gastrointestinal Melatonin

2001

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“…With respect to the gastrointestinal tract, systemic effects may be expected, as it is released into the blood stream in response to food intake (Bubenik, 2002(Bubenik, , 2008. Due to its unique lipophilic nature (Hardeland et al 2011;Chava & Sirisha, 2012), circulating melatonin crosses the cell membranes and distributes easily into tissues and biological fluids; it occurs in milk (Cohen Engler et al 2012), bile (Messner et al 2001), cerebrospinal fluid (Tan et al 2010), urine and saliva (Vakkuri, 1985;de Almeida et al 2011;Almughrabi et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Subcellular distribution of melatonin receptors in human parotid glands

et al. 2013

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The hormone melatonin influences oral health through a variety of actions, such as anti-inflammatory, antioxidant, immunomodulatory and antitumour. Many of these melatonin functions are mediated by a family of membrane receptors expressed in the oral epithelium and salivary glands. Using immunoblotting and immunohistochemistry, recent studies have shown that the melatonin membrane receptors, MT1 and MT2, are present in rat and human salivary glands. To date, no investigation has dealt with the ultrastructural distribution of the melatonin receptors. This was the aim of the present study, using the immunogold method applied to the human parotid gland. Reactivity to MT1 and, with less intensity, to MT2 appeared in the secretory granules of acinar cells and in the cytoplasmic vesicles of both acinar and ductal cells. Plasma membranes were also stained, albeit slightly. The peculiar intracytoplasmic distribution of these receptors may indicate that there is an uptake/transport system for melatonin from the circulation into the saliva.

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“…Once synthesized, the majority of melatonin diffuses directly towards the cerebrospinal fluid of the brain's third ventricle, while another fraction is released into the blood stream where it is distributed to all tissues and body fluids (Cheung et al 2006). It is found in serum, saliva (Cutando et al 2011, Novakova et al 2011, cerebrospinal fluids (Rousseau et al 1999), and aqueous humor of the eye (Chiquet et al 2006), ovarian follicular fluid, hepatogastrointestinal tissues (Messner et al 2001). Melatonin in the milk of lactating mothers exhibits a marked daily rhythm, with high levels during the night and undetectable levels during the day (Illnerova et al 1993, Sanchez-Barcelo et al 2011.…”

Section: Synthesis Distribution and Metabolismmentioning

confidence: 99%