title: Cyclooxygenase expression in splanchnic hyposensitivity to glypressin of bleeding portal hypertensive rats.
abstract: BACKGROUND
  Prostacyclin mediates, at least partly, the splanchnic vascular hyporesponsiveness to glypressin in bleeding portal hypertensive rats. This study investigated the relative contribution of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in the splanchnic hyposensitivity to glypressin in rats with portal hypertension induced by partial portal vein ligation (PVL).
  
  
  METHODS
  Fourteen days after the operation, the rats were divided into without- and with-bleeding groups. Three series of PVL rats were used to investigate (i). the haemodynamic effects of glypressin (0.07 mg x kg(-1) intravenously), (ii). COX-1/COX-2 mRNA expression over abdominal aorta and superior mesenteric artery and (iii). plasma levels of 6-keto-prostaglandin-F1alpha. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of glypressin.
  
  
  RESULTS
  Splanchnic hyposensitivity to glypressin was demonstrated in the haemorrhage-transfused PVL rats with enhanced COX-1 expression of superior mesenteric artery and increased plasma levels of 6-keto-prostaglandin-F1alpha. There were no differences in the COX-2 expression of superior mesenteric artery and COX-1 and COX-2 expressions of abdominal aorta between without- and with-bleeding groups.
  
  
  CONCLUSIONS
  In portal hypertensive rats with acute haemorrhage, COX-1 over-expression in the superior mesenteric artery plays a role in mediating the splanchnic hyposensitivity to glypressin.
authors.affiliation: Taipei Veterans General Hospital, National Yang-Ming University School of Medicine, Taipei, Taiwan, China.
authors.forename: H-C
authors.initials: HC
authors.lastname: Huang
authors.forename: S-S
authors.initials: SS
authors.lastname: Wang
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chen
authors.forename: F-Y
authors.initials: FY
authors.lastname: Lee
authors.forename: F-Y
authors.initials: FY
authors.lastname: Chang
authors.forename: H-C
authors.initials: HC
authors.lastname: Lin
authors.forename: M-C
authors.initials: MC
authors.lastname: Hou
authors.forename: C-C
authors.initials: CC
authors.lastname: Chan
authors.forename: C-T
authors.initials: CT
authors.lastname: Chen
authors.forename: S-L
authors.initials: SL
authors.lastname: Wu
authors.forename: S-D
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000818:Animals; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D006439:Hemodynamics; D006470:Hemorrhage / Q000517:prevention & control; D006975:Hypertension, Portal / Q000188:drug therapy*; D008236:Lypressin / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013152:Splanchnic Circulation / Q000187:drug effects*
chemical_list: D016861:Cyclooxygenase Inhibitors; D008236:Lypressin