Effects Of β-receptor Blockers And α-receptor Blockers On Endothelin-1 Mediated Contraction Of Hepatic Stellate Cells

ObjectiveTo investigate the effects ofβ-receptor blockers andα-receptor blockers on end othelin-1 mediated contraction of hepatic stellate cells , to provide a new theore tical evidence forβ-receptor blockers combined withα-receptor blockers to reduce portal hypertension in hepatic cirrhosis .Methods1 Using cell culture techniques in vitro, Western blot were used to measure the expression ofα-AR,β1-AR andβ2-AR on protein level; immunocytochemistry was applied to detect the expression ofα-AR,β1-AR andβ2-AR in HSCs.2 Application of laser scanning confocal microscope (laser confocal scanning microscope, LSCM), using third-generation calcium fluorescent probe Fluo-3/AM observed the effect ofα-AR antagonist (phentolamine), non-selectiveβ-AR blockers (prop- ranolol),β1-AR blocker (metoprolol) andβ2-AR antagonist (ICI-118551) on normal HSCs, and ET (1.1×10-9mol / L) mediated the HSCs [Ca2+]i fluorescence intensity, cell area and maximum diameter of the change.3 Using( x±s)to represent experiemental data,using SPSS13.0 statistical software to analyze the data, P<0.05was considered significantly important.Results1 Western blot analysis demonstratedα-AR specific bands were present at about 57 k D,β1-AR specific bands at about 50 kD,β2-AR specific bands at about 47 kD andβ-actin bands at 43 kD.2 immunocytochemistry affirmed the expression ofα-AR,β1-AR andβ2-AR in HSCs,mainly located at the cytoplasm and cell membrane in a small. 3 In addition toβ1-receptor blocker(metoprolol), the rest of AR blockers an lead to HSC[Ca2+]i decreased significantly(P<0.05) ,all AR blockers on HSCs contraction had no significant effects.4 ET-1 caused a transitory marked increase of [Ca2+]i in HSC, and a significant HSC contraction, EC50 values of about 1.1×10-9mol.L-15 In addition toβ1-receptor blocker (metoprolol), the rest of AR blockers can sig- nificantly inhibit ET-1 induced HSCs[Ca2+]i increased and contraction (P<0.05), of whichβ2-AR blockers(ICI-118551) andα+β-AR blockers (phentolamine and propran- olol) are most significant.Conclusions1 HSCs can expressα-AR,β1-AR,β2-AR on protein level,mainly located on the membrene and cell membrane in a small.2 phentolamine,propranolol,ICI-118551 cannot only cause HSCs[Ca2+]i decl- ne,but also can inhibit ET-1- inducedcontraction of HSCs, of whichβ2-AR blockers (IC-I118551) andα+β-AR blockers (phentolamine and propranolol) are most significant.3 Metoprolol not cause HSC [Ca2+] i decline, not to inhibit ET-1 mediated contrac -tion of HSCs.