心肌梗死后β_2肾上腺素受体对心室肌细胞钠钙交换电流的调控作用  

The regulation effects of β_2-adrenergic receptor on I_ (NCX) in myocytes from infarcted heart

作　　者：杨蕙[1] 伍卫[1] 邓春玉[1] 邓义军[1] 

机构地区：[1]广州市第一人民医院心内科,广东广州510180

出　　处：《中国心脏起搏与心电生理杂志》2006年第5期427-430,共4页Chinese Journal of Cardiac Pacing and Electrophysiology

摘　　要：目的研究β2受体对心肌梗死（MI）后2～8周心肌细胞钠钙交换电流（INCX）的调控作用。方法雄性健康Wistar大鼠28只，随机分为：正常对照组；MI后2周、4周、8周组。以结扎心脏左前降支方法制作MI模型。正常对照组进行假手术。采用经典的酶分离心肌细胞方法，应用全细胞膜片钳技术记录INCX，观察MI后INCX的变化，予以β2受体激动剂salbutamol、β受体激动剂异丙肾上腺素及不同选择性β受体阻滞剂后INCX的变化。结果MI后8周心肌细胞IM显著增高（1．07±0．21pA／pF vs 0．51±0．12pA／pF，P〈0．05）。MI后B2受体激动显著增加心肌细胞INCX（P〈0．05），对INCX的调节作用较正常心肌细胞强。MI后选择性β2受体阻滞剂ICI118，551对B受体激动引发的心肌细胞INCX升高的抑制程度增高；选择性β2受体阻滞剂阿替洛尔对上述作用的抑制程度下降；非选择性β受体阻滞剂普萘洛尔对β受体激动引发的正常和MI后心肌细胞上述离子通道电流升高均能明显抑制。结论MI后β2受体对心肌细胞INCX的调节作用增强，提示MI后β2受体在恶性心律失常发生机制中的地位可能提高。Objective To investigate the regulation effects of β2-adrenergic receptor（β2-AR） on INcx in myocytes from infarcted heart. Methods Twenty-eight adult Wistar rats were divided into four groups at random： the control group, the two weeks, four weeks and eight weeks post-MI groups. The chest of rats were opened and a ligature was placed around the left anterior descending coronary artery. Rats in control group were sham-operated without the coronary artery ligation. After the operation, rats were fed for two, four or eight weeks respectively. Myocytes were enzymatically disassociated by Langedorff perfusion. The whole cell-patch clamp recording technique was used to record INCX in specific pipette solution and superfusion according to specific holding potential and command potential program. Results INCx in ventricular myocytes from the border zone of infarcted heart increased significantly at eight weeks after MI（ 1.07 ±0.21 pA/pF vs . 51 ±0.12 pA/pF, P 〈 0. 05）. β2-AR agonist increased INCX more strongly in myocytes from post-MI heart than in controls. β2-AR antagonist attenuated the rise of INCX induced by β-AR agonist more strongly in myocytes from post-MI heart than in controls, whereas β1-AR antagonist was opposite to β2-AR antagonist. Conclusion The regulation effects of β2-AR on INCX in myocytes are stronger after MI. It suggests that β2-AR has closer relationship with the genesis of malignant arrhythmia after MI. [ Chinese Journal of Cardiac Pacing and Electrophysiology,2006,20 （ 5 ） ：427 - 430 ]

关 键 词：心血管病学 心肌梗死 Β2肾上腺素受体 全细胞膜片钳技术 心肌细胞 钠钙交换电流 心律失常 

分 类 号：R331.38[医药卫生—人体生理学] R541.7[医药卫生—基础医学]