不同月龄大鼠心脏α1受体对血管紧张素Ⅱ1型受体和2型受体信号转导的影响  

Effect of alpha-1 adrenoceptor activation on angiotensin Ⅱ type 1 and angiotensin Ⅱ type 2 receptors signal transduction in rat heart at differentage

作　　者：师树田[1] 李艳芳[1] 

机构地区：[1]首都医科大学附属北京安贞医院心内科,北京市100029

出　　处：《中华老年医学杂志》2008年第3期209-212,共4页Chinese Journal of Geriatrics

基　　金：北京市自然科学基金资助项目（7042056）

摘　　要：目的 研究不同月龄组Wistar大鼠心脏激动α1肾上腺素受体（α1-AR）对血管紧张素Ⅱ1型受体（AT1R）和2型受体（AT2R）信号转导的影响。方法在3．5月龄、12．0月龄、18．0月龄和24．0月龄Wistar大鼠，取部分心肌组织激动AT1R，测定酪氨酸激酶活性，激动AT2R，测定胞浆型磷脂酶A2（cPLA2）活性与环磷酸鸟苷（cGMP）水平。分别与α1-AR共同激动时的相应指标比较。结果在3．5月龄和12．0月龄大鼠心肌，激动α1-AR可升高AT1R介导的酪氨酸激酶活性，而对18及24月龄大鼠AT1R介导的酪氨酸激酶活性则没有明显影响。激动α1-AR使3．5、12．0、18．0、24．0月龄组大鼠心肌AT2R介导的cPLA2活性及cGMP水平[分别为（102．7±12．7）fmol／mg心肌和（78．3±12．0）fmol／mg心肌、（81．0±9．4）fmol／mg心肌和（58．5±10．0）fmol／mg心肌、（69．8±5．6）fmol／mg心肌和（53．3±9．7）fmol／mg心肌、（57．7±8．0）fmol／mg心肌和（40．5±6．0）fmol／mg心肌]均降低（分别为P＜0．05，P＜0．01）。结论α1-AR对青年大鼠心肌AT。R的信号转导途径有增强作用，这种作用在衰老心脏减弱。α1-AR对各年龄组大鼠AT2R的信号转导途径均有抑制效应。Objective To investigate the effects of the activation of alpha-1 adrenoceptor （α1- AR） on angiotensin Ⅱ type 1（AT1） and angiotensin Ⅱ type 2（AT2） receptors （AT1R, AT2R） signal transduction in heart of rat at differentage. Methods In hearts of rats at age of 3. 5-, 12.0-, 18.0- and 24.0-months, the activities of tyrosine kinase were measured when the AT1R was activated by angiotensin Ⅱ （Ang Ⅱ ）, the activities of cytosolic phospholipase A2 （cPLA2） and the levels of cGMP were detected when the AT2R was activated by Ang Ⅱ. Results The activities of tyrosine kinase were increased significantly in 3. 5- and 12.0-month-age rats but there were no significant differences in the activities in 18.0- and 24.0-month-age rats when a,-AR and AT, R were both activated compared with just AT1R activated. The activities of cPLA2 and the levels of cGMP were all decreased significantly in all the age groups when α1-AR and AT2R [（102.7±12.7）fmol/mg vs. （78.3±12.0） fmol/mg in 3.5-month-old rats, （81.0 ± 9.4） fmol/mg vs. （58.5± 10.0） fmol/mg in 12-month-old rats, （69.8±5.6）fmol/mg vs. （53.3±9.7）fmol/mg in 18-month-old rats, （57.7±8.0）fmol/mg vs. （40.5± 6.0） fmol/mg in 24-month-old rats, all P〈0. 053 were both activated compared with just AT2R activated. Conclusions The activation of α1-AR can increase the signal transduction of AT2R in young rat heart, while the activation of α1-AR has little effect on the AT, R signal transduction in senescent heart. The action of α1-AR decreases the signal transduction of AT2R.

关 键 词：受体  肾上腺素α1 受体 血管紧张素 1型 受体 血管紧张素 2型 信号转导 

分 类 号：R686[医药卫生—骨科学]