Cyclooxygenase expression in splanchnic hyposensitivity to glypressin of bleeding portal hypertensive rats.
Λέξεις-κλειδιά
Αφηρημένη
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 In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of glypressin.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.
