Assignment of Brain Metabolites by Means of Multi-dimension NMR

^<! >H-^1 COSY和NOESY需要一个特殊的脉冲序列以及一些特定的分析程序，以便对靠近水信号的共振进行定量估计。对于大鼠脑等组织的测量，上述方法的灵敏度不高，但CH-HMQC和Super COSY方法有较好的应用前景。这些方法具有高的H灵敏度和高的~ 1C<13>分辨，不受水共振的干扰，在脑组织的NMR研究中具有很大的吸引力，在最佳情况下，可在30分钟内得到谱图。我们可以分配的丝氨酸信号存在于大鼠脑组织中，这是尚未在文献中报道。HMQC使我们能够确认报告的分配，纠正一些分配。Super COSY应用于定量测定大鼠脑组织中的主要代谢物。结果与生化分析结果一致。重要的代谢物如GABA、牛磺酸、肌醇、胆碱等的测定非常容易，而这些代谢物用2D-NMR是非常困难的。开发了新的微型NMR管，用于小样品而不损失光谱分辨率。我们成功地将灵敏度提高到标准管的3倍，并开发了一种新的谱编辑软件，以消除水信号引起的基线滚动和消除不必要的信号。我们还能够通过我们的新软件纠正涡流对光谱的影响。

^<! >H-^1 COSY and NOESY need a special pulse train as well as some specific analitical routines in order to make a quantitative estimation for the resonances closely located to the water signal. The method mentioned above were not so attractive in sensitivity for the measurement of tissues such as rat brain, but CH-HMQC and Super COSY were found promising.HMQC gets the spectra of ^<! >H sensitibity with ^<13>C resolution, without interference of water resonance, which make these methods most attractive to the studies of brain tissues by NMR.We found a spectrum could be obtained within 30 minutes in most favorable case. We could assign the signals of serine present in the rat brain tissue which was not reported yet in the literature. HMQC allowed us to confirm the reported assignments correcting some assignments.Super COSY was applied to quantitative measurements of major metabolites in rat brain tissues. The results were parallel to that of biochemical analysis. Important metabolites such as GABA,taurine, inositol, choline, etc.were easily measured which had been extremely difficult by any other mean but 2D-NMR.New micro NMR tube was developed for small samples free from losing the spectral resolution. We have succeeded in increasing the sensitivity as much as 3 times, comparing to that of the standard NMR tubes.We have developed a new software for spectral editing to cure the baseline roll caused by water signal and to eliminate unwanted signals. We were also able to correct the influence of eddy currents on the spectra by our new software.