【摘要】 为了探讨胚胎干细胞分化心肌细胞(ESCM)毒蕈碱受体的表达规律及β肾上腺素能系统对M2受体表达的影响,采用10-4mol/L维生素C体外诱导小鼠M13胚胎干细胞分化为心肌细胞,用RT-PCR检测到分化后的细胞表达心肌细胞特异性基因Nkx2.5和β肌球蛋白重链;用免疫荧光法检测到分化后的细胞表达心肌细胞特异性标志物α辅肌动蛋白.小鼠胚胎干细胞分化前表达M1和M2毒蕈碱受体,在分化过程中,M1受体表达逐渐下降,M2受体表达在第3d显著下降,此后表达逐渐增加,在第14d达到高峰;Western印迹结果显示,异丙肾上腺素明显抑制M2受体的表达,选择性β1肾上腺素受体拮抗剂CGP20712A明显上调其表达,而选择性β2肾上腺素受体拮抗剂ICI118551对其表达无影响.本实验表明,小鼠胚胎干细胞分化心肌细胞表达毒蕈碱受体,β肾上腺素能系统对M2受体表达有调控作用.更多还原

【Abstract】 To investigate the expression pattern of muscarinic receptors in cardiomyocytes derived from embryonic stem cells （ESCM） and β-adrenergic modulation of M₂ muscarinic receptor, the M13 mouse ES cells were induced by 10 -4 mol/L vitamin C to differentiate into cardiomyocytes. RT-PCR revealed that cardiac specific genes, Nkx2.5 and β-myosin heavy chain, expressed in the differentiated cells. By immunofluorescent technique, the expression of cardiac specific marker α-actinin was found in the differentiated cells. M₁ and M₂ muscarinic receptors expressed in the undifferentiated ES cells. During the process of differentiation, the expression of M₁ receptor decreased gradually, while the expression of M₂ receptor decreased significantly at differentiation day 3 and then increased, and reached the maximal level at differentiation day 14. Western blotting showed that isoprenaline inhibited the expression of M₂ receptor and CGP20712A （a selective β₁-adrenergic receptor antagonist） up-regulated the expression, whereas ICI118551 （a selective β₂-adrenergic receptor antagonist） had no effects. These results revealed that muscarinic receptors differentially expressed in ESCM and β-adrenergic systems modulated the expression of M₂ receptor.更多还原