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目的观察自主运动是否通过调节大鼠心肌细胞β2-肾上腺素受体(β2-AR)影响心功能。方法 40只大鼠随机均分为自主运动(A)组和对照(B)组,6周后酶法分离心肌细胞,分别激动或阻断β-ARs后测定心肌细胞收缩和舒张变化。结果 A组和B组间大鼠心肌细胞静息长度差异无统计学意义(P>0.05)。混合β-ARs刺激引起心肌细胞浓度依赖的正性收缩,而A组心肌细胞的反应较B组减弱(P<0.05)。与B组相比,A组心肌细胞β1-AR和β2-AR刺激的舒张率、β1-AR刺激的收缩反应无明显变化;而β2-AR刺激的收缩功能下降(P<0.05),且可被抑制性G蛋白(Gi)的阻断剂逆转。结论自主运动通过β2-AR调节大鼠心功能。
Objective To observe whether autonomic movement affects cardiac function by regulating β2-adrenergic receptor (β2-AR) in rat cardiomyocytes. Methods Forty rats were randomly divided into two groups: control group (A) and control group (B). Six weeks later, cardiomyocytes were isolated by enzymatic method. The contraction and relaxation of cardiomyocytes were measured after β-ARs were excised or blocked respectively. Results There was no significant difference in resting length of cardiomyocytes between group A and group B (P> 0.05). Mixed β-ARs stimulated cardiomyocytes concentration-dependent positive contractions, whereas responses in group A were weaker than those in group B (P <0.05). Compared with group B, the diastolic rate of β1-AR and β2-AR stimulation in group A and the contraction response of β1-AR did not change significantly, while the contractile function of β2-AR decreased (P <0.05) Reversal by blockers of inhibitory G protein (Gi). Conclusion Autonomic modulation of rat heart function via β2-AR.