Endogenous prostaglandins and afferent sensory nerves in gastroprotective effect of hydrogen sulfide against stress-induced gastric lesions.

Hydrogen sulfide (H2S) plays an important role in human physiology, exerting vasodilatory, neuromodulatory and anti-inflammatory effects. H2S has been implicated in the mechanism of gastrointestinal integrity but whether this gaseous mediator can affect hemorrhagic lesions induced by stress has been little elucidated. We studied the effect of the H2S precursor L-cysteine, H2S-donor NaHS, the H2S synthesizing enzyme (CSE) activity inhibitor- D,L-propargylglycine (PAG) and the gastric H2S production by CSE/CBS/3-MST activity in water immersion and restraint stress (WRS) ulcerogenesis and the accompanying changes in gastric blood flow (GBF).

Mechanisms of esophageal protection, gastroprotection and ulcer healing by melatonin. implications for the therapeutic use of melatonin in gastroesophageal reflux disease (GERD) and peptic ulcer disease.

Melatonin is a potent reactive oxygen metabolite scavenger and antioxidant that has been shown to influence many physiological functions of the gastrointestinal (GI) tract including secretion, motility, digestion and absorption of nutrients. The role of melatonin in gastroduodenal defense and ulcer healing has been the subject of recent investigations. Melatonin produced in the GI mucosa plays an important role in protection against noxious agents thus contributing to the maintenance of GI integrity and to esophageal protection, gastroprotection and ulcer healing.

New satiety hormone nesfatin-1 protects gastric mucosa against stress-induced injury: mechanistic roles of prostaglandins, nitric oxide, sensory nerves and vanilloid receptors.

Nesfatin-1 belongs to a family of anorexigenic peptides, which are responsible for satiety and are identified in the neurons and endocrine cells within the gut. These peptides have been implicated in the control of food intake; however, very little is known concerning its contribution to gastric secretion and gastric mucosal integrity. In this study the effects of nesfatin-1 on gastric secretion and gastric lesions induced in rats by 3.

Conversion L-tryptophan to melatonin in the gastrointestinal tract: the new high performance liquid chromatography method enabling simultaneous determination of six metabolites of L-tryptophan by native fluorescence and UV-VIS detection.

Melatonin is a major biosynthetic product of pineal gland exerting a potent antioxidant and the reactive oxygen metabolites scavenging activities but the mechanism of formation of this indole at extrapineal sources has not been fully elucidated. It is known that the gastrointestinal (GI)-tract plays an important role as a source of melatonin synthesis but the conversion of L-tryptophan into melatonin in the GI-tract of experimental animals and humans should be further examined. In this study, the conversion of L-tryptophan to melatonin was determined in the serum collected from rats administered intragastrically with this amino acid acting as melatonin precursor.

[Melatonin as a therapeutic factor in gastric ulcer healing under experimental diabetes].

Melatonin (N-acetyl-5-methoxytryptamine) is a hormon secreted mostly by the pineal gland in the brain which maintains the body's circadian rhythm. Interestingly, this indol derivative is produced by enterochromaffin-like cells (ECL) in the gastrointestinal tract (GIT) in amount about 400 fold greater than detected in the pinealocytes. Previous studies revealed that melatonin exerts beneficial action against acute gastric damage induced by stress ethanol, aspirin and ischemia-reperfusion.