摘要
目的:研究大鼠心肌梗死后心肌组织β2肾上腺素受体(β2受体)mRNA表达水平及β2受体对细胞受体后信号3’,5’-环化一磷酸腺苷酸(cAMP)含量和cAMP依赖蛋白激酶(PKA)活性作用的动态变化。方法:Wistar大鼠48只制备心肌梗死模型,随机分为梗死后2周组、4周组、8周组,另制备假手术模型为假手术组。分离心肌细胞。每毫升细胞悬液作为一份样品,按给药不同随机分为7类:①空白对照;②沙丁胺醇;③沙丁胺醇+百日咳毒素;④异丙肾上腺素;⑤异丙肾上腺素+ICI118,551(β2受体拮抗剂);⑥异丙肾上腺素+阿替洛尔;⑦异丙肾上腺素+普萘洛尔,每类10份样品,测定cAMP含量和PKA活性。以逆转录多聚酶链反应方法测定β2受体、β1受体mRNA表达水平。结果:心肌梗死后β1受体mRNA表达水平逐渐下降(P<0.05),β2受体mRNA水平在β受体中所占比例由19%升高至38%(P<0.01),差异有统计学意义;与空白对照比较,在假手术组和梗死后2周组、梗死后4周组、梗死后8周组心肌细胞,沙丁胺醇可使cAMP含量分别升高98.1%、133.6%、147.7%和150.7%(P均<0.05),差异有统计学意义。与异丙肾上腺素比较,ICI118,551仅在梗死后8周组心肌细胞可抑制异丙肾上腺素升高cAMP含量的作用(P<0.05);阿替洛尔在假手术组和梗死后2周组、梗死后4周组细胞可抑制此作用(P<0.05);普萘洛尔在4组均可抑制此作用(P<0.05)。ICI118,551仅在梗死后8周组心肌细胞可抑制异丙肾上腺素升高依赖蛋白激酶活性的作用达55.80%(P<0.05);阿替洛尔仅在假手术组和梗死后2周组心肌细胞可抑制此作用,分别为44.76%、34.59%(P均<0.05);普萘洛尔在假手术组、梗死后2周组、梗死后4周组、梗死后8周组心肌细胞均可抑制此作用,分别为49.60%、40.82%、40.64%、46.84(P均<0.05),差异有统计学意义。结论:心肌梗死后β2受体mRNA水平在β受体中所占比例升高。β2受体激动显著升高心肌细胞cAMP含量和cAMP依赖蛋白激酶活性(P<0.05),对心肌梗死后心肌细胞的作用较正常心肌细胞增强。
Objective：To investigate the mRNA expression of β2-adrenergic receptor（β2-AR） and the receptor post signaling materials cyclic AMP（cAMP） and cAMP-dependent protein kinase （PKA） activity in myocardial infarction（MI） rats. Methods ： MI model was made by ligation of rats＇ left anterior descending coronary artery. A total of 48 adult Wistar rats were randomly divided into four groups：Control group,the rats were sham operated, and 2 weeks post MI group ,4 weeks post M1 group and 8 weeks post MI group. The myocytes suspensions were untreated or treated in each group by salbutamol, isoproterenol, ICI118,551, atenolol, propranolol and pertussis toxin （ PTX ） respectively. The mRNA expression of β2-AR and β1-AR from left ventricular myocardium were detected by RT-PCR,the concentration of cAMP was determined by competitive enzyme immunoassay and the activity of PKA was determined by non-radioactive protein kinase assay. Resuhs：Compared with Control group, the mRNA expression of β1-AR was lower in MI groups（ P 〈 0. 05 ）, and the ratio of β2-AR to β-AR increased from 19% to 38% （P 〈 0. 01 ） after MI. Compared with the untreated cells,cAMP concentration was increased by salbutamol treatment in Control group and 2 weeks ,4 weeks ,8 weeks post MI group by 98.1%, 133.6%, 147.7% and 150. 7% respectively（P 〈0.05）. Compared with isoproterenol treatment,ICI118,551 decreased cAMP concentration in 8 weeks post MI group（ P 〈 0. 05 ）. Atenolol decreased cAMP in Control group ,2 weeks and 4 weeks post MI groups （P 〈 0. 05 ） ;Propranolol decreased cAMP concentration in Control and three MI groups （ P 〈 0. 05 ）. β-receptor inhibitor inhibited PKA activity in 8 weeks post MI group（ P 〈0.05）, Atenolol inhibited PKA activity in Control group and 2 weeks post MI group（ P 〈 0.05 ）, Propranolol inhibited PKA activity in Control group and three MI groups（P 〈 0. 05, respectively）. Conclusion：The ratio of β2-AR to β-AR increased after MI. β2-AR agonist increased cAMP concentration and PKA activity in myocytes in post MI rats.
出处
《中国循环杂志》
CSCD
北大核心
2009年第3期189-193,共5页
Chinese Circulation Journal
基金
广东省医学科研基金立项课题(A2007494)
