Glytan decreases portal pressure via mesentery vasoconstriction in portal hypertensive rats

AIM: To investigate the effects of Glytan on splanchnic hemodynamics and its reduction of portal pressure in portal hypertensive rats.METHODS:Glytan(Ganluotong in Chinese),is composed of salvianolic acid B and diammonium glycyrrhizinate.Portal hypertension(PHT)was induced in the rats by common bile duct ligation(BDL).Hemodynamic studies were performed using the colored microsphere method.Radioimmunoassay(RIA)was used to determine endothelin(ET)-1 levels in the mesenteric circulation.Western blotting methods were used to investigate the effect of Glytan on ET A receptor(ETAR),ET B receptor(ETBR),endothelial NO synthase(e NOS),G-protein-coupled receptor kinase(GRK)2,and β-arrestin 2 expression in the mesentery.The m RNA of ETAR and ETBR was determined using real-time polymerase chain reaction.RESULTS:Treatment with Glytan reduced portal pressure(PP)and portal territory blood flow(PTBF)and increased both mean arterial pressure(MAP)and splanchnic vascular resistance(SVR).Especially at 4wk,PP decreased by about 40%,while MAP increased by 13%,SVR increased by 12%,and PTBF decreased by about 21%.The effect of blood flow reduction was greatest in the mesentery(about 33%)at 4 wk.The mesenteric circulation ET-1 levels of BDL rats were lower and negatively correlated with PP at 4 wk.Glytan can increase mesenteric ET-1 content and inhibit ETBR,e NOS,GRK2,andβ-arrestin 2 expression in the mesentery.Moreover,Glytan showed no effect on the expression of ETAR protein and m RNA.CONCLUSION:The decreased PP and PTBF observed after Glytan treatment were related to increased mesenteric vasoconstriction and increased receptor sensitivity to vasoconstrictor.