Objective:To investigate the changes of vasoconstrictor and vasodilator functions of isolated thoracic aorta in the rats with obstructive jaundice,so as to study the mechanism for the functional changes of the aorta in rats with obstructive jaundice.Methods: Sixty male SD rats were randomly divided into bile duct ligation (BDL) group and sham operation (SO) group.The thoracic aortas were isolated at 3,7 and 14 d after surgery and the vasoconstrictor responses induced by high potassium,norepinephrine (NE) and phenylephrine (PE) gradient and the vasodilator response to SNP were tested.Another 40 male SD rats were randomly divided into BDL three-day group,BDL seven-day group,BDL 14-day group and sham operation (SO) group.The expression of α1D -AR protein in the thoracic aorta was assessed by Western blotting.Results: The vasoconstrictor responses of thoracic aorta rings in high potassium,NE,PE,and BDL rats were weaker than those in the SO group.The vasodilator response induced by SNP in the BDL group was greater than that in the SO group.The expression of α1D -AR protein in the BDL group was weaker than that in the SO group,and the expression decreased with the prolongation of obstructive time.Conclusion: The systolic and diastolic functions of isolated thoracic aorta rings are changed in cholestatic rats; the weakened systolic function might be a result of decreased expression of α1D-AR albumen.