ABSTRACT
Objective To examine the expression levels of α1-adrenergie receptor(α1-AR)and angiotensinⅡ reeeptor(ATR)subtypes in left ventricle of rats from adolescent age, middle age,presenium to senium. Methods Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to quantitate the messenger RNA (mRNA) of α1-AR and ATR subtypes in left ventricle in Wistar rats aged 3-months (adolescent age), 12-months (middle age), 18-months (presenium) and 24-months (senium). Results The expression of α1A-AR mRNA was decreased gradually with aging, and the gene expression of α1 D-AR was repressed in middle age and presenium,while the expression of a,B-AR mRNA remained unchanged during senescence. Cardiac AT1R expression was not affected by aging from adolescent age to presenium, but exhibited a remarkable up-regulation in senium There was no significant discrepancies of cardiac AT2R expression among the four different age groups. Conclusions The results suggest that there are considerable changes in mRNA levels of cardiac α1-AR and ATR subtypes with aging. The change of cardiac α1-AR and ATR expression during aging is a protective response for senescence and has an important significance in maintaining normal physiological functions of heart.