Abstract: Objective The changes in α₁-adrenergic receptor(α₁-AR) and angiotensinⅡ receptor(ATR) expressions were considered to be associated with functional decline of renal vasoconstriction,renal structure and function.This study was designed to examine the expressions of α₁-AR and ATRsubtypes in renal tissue from young adult,middle age,presenium to senium of rats.Methods Western blotting was used to quantitate the protein levels of α₁-AR and ATR subtypes in renal tissue of 3-(young adult),12-(middle age),18-(presenium) and 24-(senium) month-old Wistar rats.Results α_1A-AR expression decreased gradually with aging: α_1A-AR protein levels decreased in middle age,presenium and senium when compared with young adult rats,respectively(P<0.01).However,the expressions of α_1B-AR and α_1D-AR remained unchanged during senescence.AT₁R expressions were unaffected by aging from young adult to middle age,but exhibited a remarkable downregulation in presenim and senium(P<0.01).In addition,AT₂R expression increased significantly in senium(P<0.01).Conclusion There are considerable changes in expression levels of renal α₁-AR and ATR subtypes during aging.The downregulation of α_1A-AR expression may account for the reduced reactivity of renal α₁-AR to vasoconstrictors and the decline of renal function in senium.Both the downregulation of AT₁R and the upregulation of AT₂R can be beneficial to maintain the normal physiological function of kidney during aging.

Key words: α₁-adrenergic receptor, angiotensinⅡ receptor, subtype, kidney, aging