Civan M M, Achlama A M, Shporer M
Biophys J. 1978 Feb;21(2):127-36. doi: 10.1016/S0006-3495(78)85513-1.
Whole frog sartorius and gastrocnemius muscles were incubated in Ringer's solutions, either unenriched or enriched with H2 17Oor 2D2O. Subsequently, the rates of transverse (1/T2) and of longitudinal (1/T1) nuclear magnetic relaxation were measured for 17O, 2D, and 1H at room temperature and at 8.1 MHz. The ratio (T1/T2) for 17O was measured to be approximately 1.5-2.0, close to the value roughly estimated from the Larmor frequency dependence of 1/T1 alone over the range 4.3-8.1 MHz. On the other hand (T1/T2) for 2D and 1H were both measured to lie in the range 9-11. Insofar as the entire 17O signal was detected, the data indicate the presence of an exchange mechanism between the major fraction of intracellular water and a minor fraction characterized by enhanced rates of relaxation. Possible molecular mechanisms are presented.
将完整的青蛙缝匠肌和腓肠肌置于林格氏液中孵育，林格氏液要么未富集，要么富集了H₂¹⁷O或2D₂O。随后，在室温及8.1兆赫兹的条件下，测量了¹⁷O、²D和¹H的横向（1/T₂）和纵向（1/T₁）核磁共振弛豫速率。测得¹⁷O的比率（T₁/T₂）约为1.5 - 2.0，接近仅根据4.3 - 8.1兆赫兹范围内1/T₁对拉莫尔频率的依赖性粗略估算的值。另一方面，测得²D和¹H的（T₁/T₂）均在9 - 11的范围内。就检测到整个¹⁷O信号而言，数据表明在细胞内大部分水与以增强的弛豫速率为特征的一小部分水之间存在交换机制。文中提出了可能的分子机制。
