肥厚心肌细胞Na^+/Ca^(2+)交换活性对β-肾上腺素能药物的反应性降低  

Reduced Responsiveness of Na^+/Ca^(2+) Exchange to β-Adrenergic Stimulation in Hypertrophied Myocytes

作　　者：吕吉元[1] 范春雨[1] 武冬梅[2] 吴博威[2] 

机构地区：[1]山西医科大学第一医院心内科,山西太原030001 [2]山西医科大学

出　　处：《高血压杂志》2003年第3期234-237,共4页Chinese Journal of Hypertension

摘　　要：目的　探讨肥厚心肌细胞Na+ /Ca2 + 交换对 β -类肾上腺素能药物刺激的反应及发生这种改变的可能机制。方法　采用胶原酶消化的高血压大鼠单个心室肌细胞及全细胞膜片钳技术 ,记录Na+ /Ca2 + 交换电流并观察药物对它的影响。结果　 (1)异丙肾上腺素可浓度依赖性地增加正常及肥厚大鼠心室肌细胞的Na+ /Ca2 + 交换电流 ,但其对肥厚心室肌细胞Na+ /Ca2 + 交换电流的增强作用要弱于正常心室肌细胞 (P <0 0 5 )。 (2 )cAMP可浓度依赖性地增加正常及肥厚大鼠心室肌细胞的Na+ /Ca2 + 交换电流 ,其对正常及肥厚大鼠心室肌细胞Na+ /Ca2 + 交换电流的增强作用无差别 (P >0 0 5 )。结论　高血压大鼠心室肌细胞Na+ /Ca2 + 交换对 β 类肾上腺素能药物的反应性降低 ,可能与肥厚心肌细胞的 β-受体数目及功能、G蛋白及腺苷酸环化酶的活性改变等环节有关 ,此种反应可能是肥厚心肌收缩及舒张功能障碍的机制之一。Objective To explore response of Na +/Ca 2+ exchange to β-adrenergic stimulation in hypertrophied myocytes and the possible mechanism. Methods Using whole cell voltage clamp techniques with a ramp pulse protocol, the quasi-steady state current-voltage relationship from the isolated rat ventricular myocytes was measured. Results (1) Isoprenaline increased Na +/Ca 2+ exchange currents in a concentration-dependent manner in control and hypertrophied ventricular myocytes, but the effect is less prominent in hypertrophied ventricular myocytes than in control ventricular myocytes ( P< 0.05). (2) cAMP increased Na +/Ca 2+ exchange currents in a concentration-dependent manner to the similiar extent both in control and hypertrophied ventricular myocytes. Conclusion The ventricular myocytes in hypertension rat have reduced responsiveness of Na +/Ca 2+ exchange to isoprenaline, suggesting Na +/Ca 2+ exchange may involve in the contractile and diastole dysfunction of hypertrophied myocardium.

关 键 词：高血压 心肌肥厚 NA^+/CA^2+交换 异丙肾上腺素 CAMP 大鼠 心脏肥厚 

分 类 号：R541.3[医药卫生—心血管疾病]