【摘要】 目的 :了解心肌M2 胆碱受体抗体 (M2 Ab)对大鼠心房和心室肌cAMP含量的影响 ,并与M2 胆碱受体激动剂卡巴可 (Carb)的作用进行了对比观察。方法 :采用离体生化放射免疫分析法测定M2 Ab及M2 胆碱受体激动剂Carb对心肌cAMP含量的影响。结果 :①M2 Ab及Carb两者均可剂量依赖性抑制异丙肾上腺素 (Isoproterenol,Iso)所刺激的大鼠心房及心室肌cAMP的增加。卡巴可浓度为 2 μmol/L ,10 μmol/L ,5 0 μmol/L时可分别抑制Iso所刺激的cAMP含量 (8.5± 1.2 ) % ,(16 .2± 1.4) % ,(2 9.5± 2 .1) % ,而M2 Ab浓度为 5 0nmol/L ,10 0nmol/L ,40 0nmol/L时 ,可分别抑制 (6 .1± 0 .6 ) % ,(17.3± 1.8) % ,(31.7± 3.1) % (P <0 .0 1)。②Carb(10 μmol/L)及M2 Ab(10 0nmol/L)两者可分别抑制基础cAMP(49.2± 4.3) %和 (6 4.3± 5 .1) %。③M受体阻断剂阿托品 (Atr) (1.5 μmol/L)不但可阻断Carb对Iso的抑制反应 ,亦能阻断M2 Ab的这种反应。而相应的抗原性肽段也能阻断M2 Ab的这种反应。结论 :M2 Ab抑制Iso引起的心室肌细胞cAMP生成量的增加反应 ,类似于M受体激动剂Carb ,两者效应均通过作用于M2 受体途径实现。更多还原

【Abstract】 Aim:To study the effects of anti peptide antibodies(M 2 Ab) against the second extracellular loop of human muscarinic receptor 2 on the cAMP content in rat atria and ventricles.These effects were compared with those of the muscarinic receptor agonist carbachol (Carb).Methods:Radioimmunoassay technique,was used for determining the effects of anti pepitide antibodies and carb on cAMP content in rat ventricles.Result:①both Carb and M 2 Ab were able to inhibit the isoproterenol (Iso) stimulated cAMP production in rat atria and ventricles.Carb at 2μmol/L,10μmol/L and 50μmol/L decreased Iso stimulated cAMP production by (8.5±1.2)%,(16.2±1.4)% and (29.5±2.1)%,respectively;whereas M 2 Ab at 50nmol/L,100nmol/L and 400nmol/L decreased it by (6.1±0.6)%,(17.3±1.8)% and (31.7±3.1)% ( P <0.01),respectively.②Both Carb and M 2 Ab could also inhibit the basal cAMP content significantly.Carb at 10μmol/L and M 2 Ab at 100nmol/L decreased it by ( 49.2± 4.3)% and (64.3±5.1)%,respectively.③The inhibitory effects of both M 2 Ab and Carb on Iso stimulated cAMP production were significantly prevented by atropine at 1.5μmol/L.The inhibitory effect of M 2 Ab at 100nmol/L was almost completely abolished by the peptide (700 nmol/L) itself.Conclusion:The anti M 2 receptor antibodies display a stimulatory muscarinic activity similar to muscarinic receptor agonist,carbachol,in inhibiting isoproterenol stimulated cAMP production of ventricles.更多还原