In vivo 31P-NMR diffusion spectroscopy of ATP and phosphocreatine in rat skeletal muscle
In vivo 31P-NMR diffusion spectroscopy of ATP and phosphocreatine in rat skeletal muscle
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DOI：
10.1016/s0006-3495(00)76717-8
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发表时间：
2000-04-01
影响因子：
3.4
通讯作者：
Nicolay, K
中科院分区：
文献类型：
--
作者：
de Graaf, RA;van Kranenburg, A;Nicolay, K
本研究的目的是用P-31-核磁共振仪测定三磷酸腺苷和磷酸肌酸在完整的大鼠骨骼肌中的扩散。通过使用频率选择性刺激回波序列结合绝热射频脉冲和表面线圈信号的激励和接收，根据ATP的信噪比优化了扩散敏化光谱的获取。通过测定三磷酸腺苷和聚合酶链式反应的表观扩散系数随扩散时间的变化来研究扩散限制。通过确定扩散张量的迹线消除了取向效应。将数据拟合到圆柱形限制模型中，以估计无限扩散系数和限制隔室的径向尺寸。在37℃时，ATP和PCR的无结合扩散系数接近其体外扩散系数的90%，柱状限制室的直径分别类似于16和22微米。已知大鼠骨骼肌纤维的直径在60到80微米之间。因此，该模型表明，体内对ATP和PCR扩散的限制不是由肌膜施加的，而是由具有整体圆柱形取向的其他细胞内结构施加的。
The aim of this study was to measure the diffusion of ATP and phosphocreatine (PCr) in intact rat skeletal muscle, using P-31-NMR. The acquisition of the diffusion-sensitized spectra was optimized in terms of the signal-to-noise ratio for ATP by using a frequency-selective stimulated echo sequence in combination with adiabatic radio-frequency pulses and surface coil signal excitation and reception. Diffusion restriction was studied by measuring the apparent diffusion coefficients of ATP and PCr as a function of the diffusion time. Orientation effects were eliminated by determining the trace of the diffusion tensor. The data were fitted to a cylindrical restriction model to estimate the unbounded diffusion coefficient and the radial dimensions of the restricting compartment. The unbounded diffusion coefficients of ATP and PCr were similar to 90% of their in vitro values at 37 degrees C, The diameters of the cylindrical restriction compartment were similar to 16 and similar to 22 mu m for ATP and PCr, respectively. The diameters of rat skeletal muscle fibers are known to range from 60 to 80 mu m. The modelling therefore suggests that the in vivo restriction of ATP and PCr diffusion is not imposed by the sarcolemma but by other, intracellular structures with an overall cylindrical orientation.