抗钠钙交换体特异位点抗体对大鼠单个心室肌细胞钙瞬变的影响

目的:观察抗钠钙交换体(Sodium calcium exchanger,NCX)特异位点124HNFTAGDLGPSTIVGSAAFNMF145 抗体对正常成年大鼠心室肌细胞钙瞬变的影响。方法:利用Langendorff 灌流方法,分离得到单个大鼠心室肌细胞;负载荧光染料Fura-2/ AM 和2%牛血清白蛋白后,利用离子影像分析系统记录激发光为340 nm 和380 nm 时心室肌细胞成对系列图像,计算钙瞬变峰值(F340/ F380)、细胞钙恢复90%时程(TR90 )以及钙敏感性(F340/ F380 与细胞缩短数值的比值)。结果:抗NCX 特异位点抗体可以增加正常成年大鼠单个心室肌细胞F340/ F380,缩短TR90 ,对钙敏感性无显著影响;尼卡地平和KB-R7943 分别预处理心室肌细胞可以抵消大部分抗体对F340/ F380 和TR90 的增加或缩短效应,联合使用二者预处理心室肌细胞后,该抗体对钙瞬变不再有显著影响。结论:抗NCX 特异位点124 HNFTAGDLGPSTIVGSAAFNMF145 抗体可以增加心室肌细胞钙瞬变峰值,同时缩短细胞钙恢复时程,这种效应主要与其激动L-型Ca2+通道和NCX 的作用有关。

Effects of site specific antibody of Na+-Ca2+ exchanger on calcium transient in single ventricular myocytes of rats

Objective:To investigate the effects of site specific(124 HNFTAGDLGP STIVGSAAFNMF145 ) antibody of Sodium calcium exchanger(NCX) on calcium transient in single ventricular myocytes of normal adult rats.Methods: Isolated adult rat hearts were perfused using Langendorff method and single ventricular myocytes were then obtained.The ventricular myocytes were incubated with Fuar-2/ AM and 2% bovine serum albumin for about 40 min and then,the fluorescence images were recorded when excitation wavelengths were 340 nm and 380 nm using ion imaging system.Fluorescence value F340/ F380,length of cell shortening,time to 90% restore(TR90 )and calcium sensitivity(ratio of F340/ F380 and cell shortening) were calculated.Results: The site specific antibody of NCX increased F340/ F380 and decreased TR90 in single ventricular myocytes,but had no more significant effect on calcium sensitive-ty.Pretreatment with KB-R7943 or Nicardipine could significantly inhibit the TR90 decrease or F340/ F380 increase induced by the anti- body.Pretreating ventricular myocytes with combination of KB-R7943 and Nicardipine,the antibody had no more significant effects on calcium transient.Conclusion: Site specific (124 HNFTAGDLGPSTIVGSAAFNMF145 )antibody of NCX could increase calcium transient and accelerate the decrease of intracellular calcium during diastole,which mainly related to its effects of activating L-type Ca2+ channel and NCX.