α_(1)-肾上腺素受体介导去甲肾上腺素促大鼠培养心肌细胞肥大及肌球蛋白基因表达

α_(1)Adrenergic receptor mediates the norepinephrine-induced hypertrophy and expression of myosin heavy chain genes in cultured rat cardiomyocytes

目的 :探讨去甲肾上腺素 (NE)促心肌细胞肥大及肌球蛋白重链 (MHC)基因表达作用的受体机制。方法 :采用测定心肌细胞直径、数目及 3H-亮氨酸 (3H- L eu)掺入率的方法 ,观察 NE及哌唑嗪 (PRAZ)对大鼠培养心肌细胞肥大的影响 ,以斑点杂交分析 NE、PRAZ在心肌细胞 MHC基因表达中的作用。结果 :NE明显促进心肌细胞直径增大 (P <0 .0 1)及 3H- L eu掺入率的增加 (P <0 .0 1) ,并明显诱导心肌细胞β- MHC基因表达 ,α- MHC基因表达相应减少 ,PRAZ完全阻断 NE的上述作用。结论 :NE可促进心肌细胞肥大及 MHC基因表达 ,该作用可能通过α1 肾上腺素受体介导。

Objective:To study the mechanism of receptor on norepinephrine(NE)stimulating hypertrophy and expression of myosin heavy chain(MHC) genes in cultured rat cardiomyocytes.Method:The effects of NE and prazosin(PRAZ) on hypertrophy and MHC expression in cultured rat cardiomyocytes were observed by measuring the diameter and number of cardiomyocytes,incorporation of 〔 3H〕 Leucine( 3H-Leu) and dot-bot hybridization.Result:NE significantly increased the diameter and 3 H-Leu incorporation of cardiomyocytes(P< 0.01 ),and induced the expression of β-MHC gene,PRAZ completely blocked the effects of NE.Conclusion:NE can stimulate hypertrophy of cardiomyocytes and expression of MHC genes.This effect may be mediated by α 1adrenergic receptor.