Seo Y, Murakami M, Suzuki E, Kuki S, Nagayama K, Watari H
Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Biochemistry. 1990 Jan 23;29(3):599-603. doi: 10.1021/bi00455a001.
Intracellular K of the perfused rat mandibular salivary gland was measured by 39K NMR spectroscopy at 8.45 T. Multiple-quantum NMR arising from multiple-exponential decay was used to eliminate the resonance due to extracellular K in the perfused gland at 25 degrees C. The resonance due to intracellular K consisted of two Lorentzian signals stemming from the [spin 1/2 to -1/2] coherence (sharp resonance) and the [spin -1/2 to -3/2], [spin 3/2 to 1/2] coherences (broad resonance). The transverse relaxation time (T2) corresponding to the [spin 1/2 to -1/2] coherence was ca. 2.5 ms, and that corresponding to the [spin -1/2 to -3/2], [spin 3/2 to 1/2] coherences was ca. 0.4 ms. The relaxation time of the double-quantum coherence of rank 3 (originating from product operators like Ix2Iz) was determined to be ca. 0.2 ms. These results suggest the possibility of the presence of a single homogeneous population of intracellular K with a correlation time of ca. 2.5 x 10(-8) s and a quadrupolar coupling constant of ca. 1.4 MHz.
在8.45 T磁场下，采用39K核磁共振波谱法测定灌注大鼠下颌下唾液腺细胞内的钾含量。利用多指数衰减产生的多量子核磁共振消除25℃时灌注腺体外细胞外钾的共振。细胞内钾的共振由两个洛伦兹信号组成，分别源于[自旋1/2到-1/2]相干（尖锐共振）和[自旋-1/2到-3/2]、[自旋3/2到1/2]相干（宽共振）。对应于[自旋1/2到-1/2]相干的横向弛豫时间（T2）约为2.5 ms，对应于[自旋-1/2到-3/2]、[自旋3/2到1/2]相干的横向弛豫时间约为0.4 ms。三阶双量子相干的弛豫时间（源于诸如Ix2Iz等乘积算符）测定为约0.2 ms。这些结果表明，可能存在单一均匀的细胞内钾群体，其相关时间约为2.5×10^(-8) s，四极耦合常数约为1.4 MHz。
