The effects of physical and psychological stress on the gastrointestinal tract: Lessons from animal models
ABSTRACT Physical and psychological stresses are widely accepted as triggers and / or modifiers of the clinical course of diverse gastrointestinal disorders such as peptic ulcer, irritable bowel syndrome or inflammatory bowel disease. Growing experimental evidence from a variety of models such as immobilization, thermal injury or early maternal deprivation in laboratory animals uniformly supports the ability of stress to induce the development of gastric ulcers, altered gastrointestinal motility and ion secretion, and increased intestinal permeability leading to the passage of antigens to the lamina propria and bacterial translocation. Stress can also synergize with other pathogenic factors such as Helicobacter pylori, non-steroidal anti-inflammatory drugs or colitis-inducing chemicals to produce gastrointestinal disease. The brain-gut axis provides the anatomical basis through emotions and environmental influences modulate the gastrointestinal function through the regulation of gastrointestinal immune system and mucosal inflammation; in this sense, mucosal mast cells - at cellular level - and corticotropin releasing factor (CRF) - at molecular level - seem to play a crucial role. On the other hand, an array of adaptive responses have been evolved in order to maintain the homeostasis and to ensure the survival of the individual. In the gut mucosa anti-inflammatory pathways counteract the deleterious effect of the stressful stimuli on the gastrointestinal homeostasis. In the present review we discuss the several experimental approaches used to mimic human stressful events or chronic stress in laboratory animals, the evidence of stress-induced gastrointestinal inflammation and dysfunction derived from them, and the involved cellular and molecular mechanisms that are being discovered during the last years.
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ABSTRACT: Arctium lappa L. (A. lappa L) is an important medicinal plant used in Brazil to heal gastric ulcers. This study reveals the pharmacological action of this traditional medicine use. The aqueous extract obtained from the liquid-liquid partition of the 70% ethanol extract of the A. lappa was challenged against in vivo Hydrochloric acid (HCl)/ethanol-, piroxicam-and cold restrained stress-induced gastric ulcer, and pylorus ligation assays. NO-synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) and SH blocker (N-ethylmaleimide (NEM) were used to evaluate the participation of cytoprotective factors in ALT gastroprotection. Antiulcerogenic action of A. lappa L was evaluated in mice at doses of 50, 100 or 200 mg/kg. A. lappa L showed elevated gastroprotective action in all in vivo experimental models, but did not interfere with gastric secretion. The mechanisms involved in the gastroprotective action of A. lappa L are related to mucosal protector factors, such as nitric oxide (NO) and sulfhydryl (SH) compounds. This species is a promising herbal drug due to its effectiveness in the gastroprotection, which is in accordance with an ethnopharmacological use against gastric ulcers.
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ABSTRACT: Corticotrophin releasing hormone (CRH) is believed to mediate stress-induced behaviors, implying a broader, integrative role for the hormone in the psychological stress response, and studies on CRH in physical stress are few. This study was undertaken to investigate whether CRH plays an important role in cerebral infarction-related gastrointestinal barrier dysfunction.
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ABSTRACT: The maternal separation protocol in rodents is a widely recognized model of early life stress allowing acute and chronic physiological consequences to be studied. An (1)H NMR-based metabolomic approach was applied to urines to evaluate the systemic metabolic consequences of maternal separation stress in female rats after the beginning of weaning and four weeks later when the rats were reaching adulthood. Furthermore, since maternal separation is considered as a model mimicking the inflammatory bowel syndrome, the lactulose/mannitol test was used in order to evaluate the influence of postnatal maternal separation on gut permeability and mucosal barrier function by (1)H NMR spectroscopy analysis of urine. The results showed no statistical differences in gut permeability due to maternal separation . The application of ANOVA simultaneous component analysis allowed the contributions of physiological adaptations to the animal's development to be separated from the metabolic consequences due to postnatal stress. Systemic metabolic differences in the maternally separated pups were mainly due to the tryptophan/NAD pathway intermediate levels and to the methyladenosine level. Urinary NMR-based metabolic profiling allowed us to disentangle the metabolic adaptive response of the rats to postnatal stress during the animal's growth highlighting the metabolic changes induced by weaning, gut closure and maturity.Journal of Proteome Research 10/2014; DOI:10.1021/pr500748r · 5.00 Impact Factor