ABSTRACT
Objective To observe the effects of sympathectomy on the function and the expression level of angiotensin Ⅱ type 1 receptor(AT_(1)R).Methods Newborn male Wistar rats' sympathetic nerve was destroyed by 6-hydroxydopamine(6-OHDA),and then following parameters were observed after 11 weeks: pressor and vasoconstrictive effects of AngⅡ,the affinity of -AngⅡ to AT_(1)R in myocardium,the level of mRNA expression of AT_(1)R in vessel smooth muscle.Results The pressor and vasoconstrictive effects induced by AngⅡand the mRNA expression of AT_(1)R in vessel smooth muscle enhanced substantially in adult rats who had been performed sympathectomy at juvenile period.There was also an enhancement in B_(max) of AT_(1)R in myocardium of the rats performed with sympathectomy,while no change occurred in K_(D).Conclusion In rats performed with sympathectomy,the expression level of AT_(1)R rises remarkably.The pressor and vasoconstrictive effects induced by AngⅡenhance consequently. These might be the reasons that blood pressure and heart rate do not reduce after sympathectomy.