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目的:探讨长期糖尿病大鼠心脏肾上腺素受体(AR)的改变及其与心功能变化之间的关系。方法:采用链脲佐菌素(STZ)注射造成胰岛素依赖性糖尿病大鼠模型,放射配体结合实验和离体左心房收缩功能实验等方法观察心脏AR及功能的改变。结果:与同龄对照大鼠相比,糖尿病大鼠心脏β-AR的最大结合容量(Bmax)下降34%(P<0.05),KD值不变;心脏α1-AR Bmax无显著改变。糖尿病大鼠左心房β-AR介导的最大收缩反应(Rmax)较对照组下降64%(P<0.05);α1-AR介导的最大收缩反应增加36 %(P<0.05),pD2值不变。结论:长期糖尿病大鼠心脏β-AR介导的最大收缩反应降低,其可能与β-AR数量减少有关。α1-AR介导的最大收缩反应代偿性增强,其可能与受体后信号转导效应增强有关。
Objective: To investigate the changes of cardiac adrenergic receptor (AR) and its relationship with cardiac function in chronic diabetic rats. Methods: Cardiac AR and functional changes were observed by streptozotocin (STZ) injection in rats with insulin-dependent diabetes mellitus, radioligand binding assay and isolated left atrial systolic function test. Results: Compared with the same age control rats, the maximum β-AR binding capacity (Bmax) of diabetic rats decreased by 34% (P <0.05), while the KD value remained unchanged. The α1-AR Bmax of heart did not change significantly. The left ventricular β-AR-mediated maximal contractile response (Rmax) in diabetic rats decreased by 64% (P <0.05), the maximal contractile response induced by α1-AR increased by 36% (P <0.05) change. CONCLUSION: The maximal contractile response induced by β-AR in the heart of long-term diabetic rats is decreased, which may be related to the decrease of β-AR. α1-AR-mediated maximal contractile response compensatory enhancement, which may be related to post-receptor signal transduction enhancement.