Voltage‐controlled Ca2+ release in normal and ryanodine receptor type 3 (RyR3)‐deficient mouse myotubes
Voltage‐controlled Ca2+ release in normal and ryanodine receptor type 3 (RyR3)‐deficient mouse myotubes
复制标题
正常和兰尼碱受体 3 型 (RyR3) 缺陷的小鼠肌管中电压控制的 Ca2+ 释放
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
W. Melzer
中科院分区：
文献类型：
--
作者：
B. Dietze;F. Bertocchini;V. Barone;A. Struk;V. Sorrentino;W. Melzer
1 原代培养的肌管源自正常小鼠 (RyR3+/+) 和具有消除兰尼碱受体 3 型亚型表达的靶向突变的小鼠 (RyR3−/−) 的隔膜卫星细胞。使用全细胞膜片钳技术，在逐步去极化过程中测量 L 型 Ca2+ 电流。同时，用荧光指示剂染料 fura-2 记录细胞内 Ca2+ 瞬变。 2 对 Ca2+ 与指示剂染料的非瞬时结合进行校正并考虑 Ca2+ 与细胞内成分结合的动力学后，获得了肌浆网 (SR) 中 Ca2+ 释放速率的时程估计值。 3 计算得出的 SR Ca2+ 释放通量在电压钳去极化开始后不到 12 毫秒内出现明显峰值，此后迅速下降至低五倍、几乎稳定的水平。去极化结束后迅速下降。 4 正常和 RyR3 缺陷肌管中的信号显示，Ca2+ 电导的激活以及来自 SR 的 Ca2+ 流出的幅度、时间进程和电压依赖性没有显着差异。 5 总之，本文报道的电压控制 Ca2+ 释放的特征与成熟哺乳动物肌肉纤维的特征相似。与 RyR3 缺陷肌纤维的收缩特性中观察到的差异相反，在肌管中无法检测到 RyR3 对兴奋-收缩耦合的贡献。
1 Primary cultured myotubes were derived from satellite cells of the diaphragm obtained from both normal mice (RyR3+/+) and mice with a targeted mutation eliminating expression of the type 3 isoform of the ryanodine receptor (RyR3−/−). Using the whole‐cell patch clamp technique, L‐type Ca2+ currents were measured during step depolarizations. Simultaneously, intracellular Ca2+ transients were recorded with the fluorescent indicator dye fura‐2. 2 After correction for non‐instantaneous binding of Ca2+ to the indicator dye and taking into account the dynamics of Ca2+ binding to intracellular constituents, an estimate of the time course of the Ca2+ release rate from the sarcoplasmic reticulum (SR) was obtained. 3 The calculated SR Ca2+ release flux exhibited a marked peak within less than 12 ms after the onset of the voltage‐clamp depolarization and fell rapidly thereafter to a five times lower, almost steady level. It declined rapidly after termination of the depolarization. 4 Signals in normal and RyR3‐deficient myotubes showed no significant difference in the activation of Ca2+ conductance and in amplitude, time course and voltage dependence of the Ca2+ efflux from the SR. 5 In conclusion, the characteristics of voltage‐controlled Ca2+ release reported here are similar to those of mature mammalian muscle fibres. In contrast to differences observed in the contractile properties of RyR3‐deficient muscle fibres, a contribution of RyR3 to excitation‐contraction coupling could not be detected in myotubes.
影响因子：
5.5
作者：
BAYLOR, SM;CHANDLER, WK;MARSHALL, MW
通讯作者：
MARSHALL, MW
心脏和骨骼兰尼碱受体的功能不均匀。
DOI：
10.1073/pnas.94.3.1019
发表时间：
1997
影响因子：
11.1
作者：
Nakai,J;Ogura,T;Protasi,F;Franzini-Armstrong,C;Allen,PD;Beam,KG
通讯作者：
Beam,KG