Feher J J, Manson N H, Poland J L
Department of Physiology, Medical College of Virginia, Richmond 23298.
Arch Biochem Biophys. 1988 Aug 15;265(1):171-82. doi: 10.1016/0003-9861(88)90382-7.
The rate and capacity of oxalate-supported calcium uptake was measured in homogenates of rat fast, slow, and cardiac muscle. The contribution of the releasing fraction of the sarcoplasmic reticulum (SR) to the calcium uptake abilities was estimated using ruthenium red or ryanodine to block the release channel. A relatively small fraction (12-20%) of the calcium pumping activity was associated with the release channel in skeletal muscle compared to 50% or more in cardiac muscle. The total capacity of the SR in the muscle types was in the ratio 1:0.75:1.5 for cardiac, slow, and fast muscle, respectively, while the rates of uptake were in the ratio 1:3.8:14.4. The major difference in the muscle types appears to be the density of pumping activity in the SR rather than the volume of the SR. The difference in the density of pumping activity is due to intrinsic differences in the kinetics of the calcium pump units and in their surface density.
在大鼠快肌、慢肌和心肌的匀浆中测量了草酸盐支持的钙摄取速率和能力。使用钌红或兰尼碱阻断释放通道，估算肌浆网（SR）释放部分对钙摄取能力的贡献。与心肌中50%或更多相比，骨骼肌中相对较小比例（12 - 20%）的钙泵活性与释放通道相关。心肌、慢肌和快肌中SR的总容量分别为1:0.75:1.5的比例，而摄取速率为1:3.8:14.4的比例。肌肉类型之间的主要差异似乎在于SR中泵活性的密度，而非SR的体积。泵活性密度的差异是由于钙泵单元动力学及其表面密度的内在差异所致。
