title: Gastroprotective effect of orexin-A and heme oxygenase system.
abstract: BACKGROUND
  Orexin-A, besides playing an important role in the mechanism of food intake, exhibits a potent gastroprotective action against the formation of acute gastric mucosal injury. The aim of the present study was to determine the effect of administered orexin-A against ischemia-reperfusion (I/R)-induced gastric injury on the expression of heme oxygenase (HO)-1 and HO-2 in gastric tissue.
  
  
  METHODS
  Wistar rats were subjected to 30 min of ischemia followed by 3 h reperfusion. Orexin-A was infused at a dose of 500 pmol/kg/min during the I/R period. The lesion area was measured by stereomicroscope. The myeloperoxidase activity and 4-hydroxinonenol-malondialdehyde content of gastric mucosa were evaluated spectrophotometrically, and the gastric tumor necrosis factor-α was measured by enzyme linked immune sorbent assay. The expression of HO-1 and HO-2 was determined by Western blotting analysis.
  
  
  RESULTS
  Orexin-A significantly decreased the I/R-induced gastric lesions, myeloperoxidase activity, and 4-hydroxinonenol-malondialdehyde concentration in gastric tissue exposed to I/R. The gastroprotective effect of orexin-A in gastric I/R model was accompanied by the increase in HO-2 expression and the decrease in HO-1 expression.
  
  
  CONCLUSIONS
  Orexin-A exerts a protective action on gastric mucosa subjected to I/R, and this effect is associated with the reduction of neutrophil infiltration and lipid peroxidation in gastric tissue in addition to the increase in HO-2 expression due to the administration of orexin-A.
authors.affiliation: Department of Physiology, Faculty of Medicine, Near East University, Lefkosa, Cyprus.
authors.forename: Burcu
authors.initials: B
authors.lastname: Gemici
authors.affiliation: Department of Physiology, Faculty of Medicine, Near East University, Lefkosa, Cyprus.
authors.forename: Ruken
authors.initials: R
authors.lastname: Tan
authors.affiliation: Department of Physiology, Faculty of Medicine, Akdeniz University, Antalya, Turkey.
authors.forename: Ilknur
authors.initials: I
authors.lastname: Birsen
authors.affiliation: Department of Physiology, Faculty of Medicine, Akdeniz University, Antalya, Turkey. Electronic address: nimetu@akdeniz.edu.tr.
authors.forename: V Nimet
authors.initials: VN
authors.lastname: İzgüt Uysal
mesh_terms: D000818:Animals; D004353:Drug Evaluation, Preclinical; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008315:Malondialdehyde / Q000031:analogs & derivatives / Q000378:metabolism; D009479:Neuropeptides / Q000494:pharmacology* / Q000627:therapeutic use; D018377:Neurotransmitter Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000068797:Orexins; D009195:Peroxidase / Q000378:metabolism; D011897:Random Allocation; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000517:prevention & control; D013270:Stomach / Q000187:drug effects* / Q000201:enzymology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D000068797:Orexins; D014409:Tumor Necrosis Factor-alpha; D008315:Malondialdehyde; D009195:Peroxidase; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C105245:heme oxygenase-2
keywords: Gastric; Heme oxygenase-1; Heme oxygenase-2; Ischemia–reperfusion; Lesion; Orexin-A