Bkaily G, Sculptoreanu A, Jacques D, Jasmin G
Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, Quebec, Canada.
Mol Cell Biochem. 1997 Nov;176(1-2):199-204.
In the present study, the whole-cell voltage clamp technique was used in order to record the T- and L-type Ca2+ currents in single heart cells of newborn and young normal and hereditary cardiomyopathic hamsters. Our results showed that the I/V relationship curve as well as the kinetics of the L-type Ca2+ currents (ICa(L)) in both normal and cardiomyopathic heart cells were the same. However, the proportion of myocytes from normal heart hamster that showed L-type ICa was less than that of heart cells from cardiomyopathic hamster. The I/V relationship curve of the T-type ICa (ICa(T)) was the same in myocytes of both normal and cardiomyopathic hamsters. The main differences between ICa(T) of cardiomyopathic and normal hamster are a larger window current and the proportion of ventricular myocytes that showed this type of current in cardiomyopathic hamster. The high density of ICa(T) as well as the large window current and proportion of myocytes showing ICa(T) may explain in part Ca2+ overload observed in cardiomyopathic heart cells of the hamster.
在本研究中，采用全细胞膜片钳技术记录新生及幼年正常和遗传性心肌病仓鼠单个心肌细胞中的T型和L型Ca2+电流。我们的结果表明，正常和心肌病心肌细胞中L型Ca2+电流（ICa(L)）的I/V关系曲线以及动力学是相同的。然而，正常心脏仓鼠显示L型ICa的心肌细胞比例低于心肌病仓鼠的心脏细胞。正常和心肌病仓鼠心肌细胞中T型ICa（ICa(T)）的I/V关系曲线相同。心肌病仓鼠和正常仓鼠ICa(T)之间的主要差异在于更大的窗电流以及心肌病仓鼠中显示这种类型电流的心室肌细胞比例。ICa(T)的高密度以及大窗电流和显示ICa(T)的心肌细胞比例可能部分解释了仓鼠心肌病心肌细胞中观察到的Ca2+超载。
