生理学报Acta Physiologica Sinica, June 25

研究论文

β2-肾上腺素受体在新生大鼠心肌成纤维细胞中的分布及其促增殖作用

尹峰, 吕志珍, 韩启德, 张幼怡*

北京大学第三医院血管医学研究所, 分子心血管学教育部重点实验室, 北京 100083

摘要: 为了明确β-肾上腺素受体(AR) 亚型在新生大鼠心肌成纤维细胞中的分布及其在成纤维细胞增殖反应中的作用, 采用放射配体结合实验和[3H]-thymidine掺入法检测了新生大鼠心肌成纤维细胞的β-AR密度和DNA合成速率。结果显示, 在培养心肌细胞和心肌成纤维细胞中β-AR密度(Bmax)和解离常数(KD)无显著性差异; 竞争抑制曲线分析结果提示, 心肌成纤维细胞对CGP 20712A和ICI 118551单位点拟合均显著优于两位点拟合(P<0.01), 表现为对选择性β1-AR拮抗剂CGP 20712A的低亲和性(IC50值: 10.1 μmol/L)和对选择性β2-AR拮抗剂ICI 118551的高亲和性(IC50值: 0.147 μmol/L)。异丙肾上腺素(ISO)促心肌成纤维细胞增殖作用可被ICI 118551和心得安(非选择性β-AR拮抗剂)完全抑制, 而CGP 20712A则无此作用。上述结果提示, 在培养心肌成纤维细胞中β2-AR亚型占绝对优势, 并且ISO引起的心肌成纤维细胞增殖反应是由β2-AR介导的。

关键词: β-肾上腺素受体; 放射配体结合实验; 心肌成纤维细胞; 增殖

中图分类号: Q463

Expression of β2-adrenergic receptor and its effect on the proliferation of neonatal rat cardiac fibroblasts

YIN Feng, LU Zhi-Zhen, HAN Qi-De, ZHANG You-Yi*

Institute of Vascular Medicine, Peking University Third Hospital , The Reference Laboratory of Ministry of Education for Molecular Cardiovasology, Beijing 100083

Abstract: The expression of β-adrenergic receptor subtypes and its effect on neonatal rat cardiac fibroblast proliferation were investigated by radioligand binding assay and [3H]-thymidine incorporation analysis, respectively. The results indicated that there was no significant difference in the β-adrenergic receptor density (Bmax) and affinity (KD) between cardiomyocytes and cardiac fibroblasts. The [125I]-pindolol competitive inhibition curves (ICI 118551 and CGP 20712A) were significantly better fit in a one-site model in membrane preparation of cardiac fibroblasts. In cultured cardiac fibroblasts, 0.1 μmol/L isoproterenol-induced [3H]-thymidine incorporation was completely inhibited by a selective β2-AR antagonist ICI 118551, or a non-selective β-AR antagonist propranolol, but not by CGP 20712A, a selective β1-AR antagonist. These results suggest that isoproterenol-induced cardiac fibroblast proliferation is mediated by β2-AR, the preponderant β-AR subtype in cardiac fibroblasts.

Key words: β-adrenergic receptor; radioligand binding assay; cardiac fibroblasts; proliferation