风湿性心脏病患者体外循环后心肌β受体系统解偶联

Uncoupling of Myocardial Beta adrenergic Receptor in Rheumatic Heart Disease Patients after Cardiopulmonary Bypass

目的研究体外循环（ＣＰＢ）对风湿性心脏病患者心肌β受体系统的影响。方法采用放射免疫分析法测定了１２例风湿性心脏病患者ＣＰＢ前后心肌β受体密度、腺苷酸环化酶（ＡＣ）活性、异丙肾上腺素介导的腺苷酸环化酶最大活性（ＩＳＯ－ＡＣ）。结果ＣＰＢ前后β受体密度、腺苷酸环化酶活性均无明显改变；ＣＰＢ后ＩＳＯ－ＡＣ（１０．２９±３．６５ｐｍｏｌｃＡＭＰ／ｍｇｐｒ·ｍｉｎ）较ＣＰＢ前（１５．９８±４．６３ｐｍｏｌｃＡＭＰ／ｍｇｐｒ·ｍｉｎ）明显降低。结论风湿性心脏病患者ＣＰＢ后β受体系统解偶联，对儿茶酚胺反应性降低。

Objective To study the effects of cardiopulmonary bypass (CPB) on human cardiac beta adrenergic receptor system in rheumatic heart disease patients. Methods Right atrial beta adrenergic receptor density, adenylate cyclase activity and maximal isoproterenol stimulated adenylate cyclase activity (ISO AC) were determined by radioimmunoassay in 12 rheumatic heart disease patients who underwent open heart surgery before and after CPB. Results Basal adenylate cyclase activity were stable at 4.29±1.78(pre CPB) and 4.16±1.28 pmol cAMP/mg pr·min (post CPB). Beta adrenergic receptor densities were also stable at 32.52±7.89fmol/mg(pre CPB) and 29.96±7.07 fmol/mg(post CPB). But after CPB, ISO AC was decreased from 15.98±4.63 to 10.29± 3 65 pmol cAMP/mg pr·min. Conclusion The data shows that CPB causes beta adrenergic receptor system uncoupling. It might be one of the causes of post CPB low cardiac output in such patients.