MULTIPLE QUANTUM NMR STUDIES OF SODIUM AND POTASSIUM IN THE RAT BRAIN

我们以前开发了一种新的方法来研究跨膜 利用不同核磁共振弛豫技术研究完整脑内的离子梯度 胞内和胞外离子的次数。双量子核磁共振 光谱比传统的单量子核磁共振更灵敏 松弛时间变化的光谱。双量子和单量子 大鼠脑组织的量子~(23)Na和~(39)K核磁共振谱 活着。死后，双量子23Na核磁共振信号增加了 三倍，而单量子信号减少了20%。 这一结果与众所周知的钠离子流入是一致的。 进入细胞内，并表明双量子钠和钾 核磁共振在显示大脑受损区域方面可能很有用。 我们已经在多个方向上扩展了这一方法。首先，我们 扩展了在活体研究猫脑的方法，并灌流了 老鼠肝。其次，我们用双量子~(23)Na核磁共振进行了研究 钠在完整的大脑中的区隔。第三，我们联合起来 多量子~(23)Na核磁共振与~(31)P核磁共振的相关性研究 在多量子钠核磁共振信号的变化和 细胞能量学的变化。 去年我们进行了一次全面的双量子23钠 移位试剂用于肝脏灌流的研究。结果表明， 在这个器官中，大部分双量子信号来自 细胞内的钠离子。

We previously developed a new approach for studying trans-membrane ion gradients in the intact brain utilizing the different NMR relaxation times of intracellular and extracellular ions. Double quantum NMR spectra are more sensitive than conventional single quantum NMR spectra to changes in relaxation times. Double quantum and single quantum 23Na and 39K NMR spectra were obtained from rat brain in vivo. Upon death, the double quantum 23Na NMR signal increased by a factor of three, while the single quantum signal decreased by 20%. The results are consistent with the well-known influx of sodium ions into the cell, and suggest that double quantum sodium and potassium NMR may be useful in visualizing compromised regions of the brain. We have extended this approach in a number of directions. First we extended the approach to study the cat brain in vivo, and the perfused rat liver. Second, we used double-quantum 23Na NMR to study compartmentation of sodium in the intact brain. Third, we combined multiple-quantum 23Na NMR with 31P NMR to study the correlation between changes in the multiple-quantum sodium NMR signals and changes in cellular energetics. In the last year we performed a comprehensive double quantum 23 Na study of perfused liver using shift reagents. The results indicate that, in this organ, most of the double-quantum signal arises from intracellular sodium ions.