NMR-spectrophotometer integrated device to monitor neuronal activity

1. 本实验室将异核多量子相干（HMQC）技术与无创定位技术相结合，开发了一种高灵敏度的体内^<13>C核磁共振波谱技术，并将快速扫描回波平面成像（EPI）方法应用于MRI。用^<13>C标记的葡萄糖注射到活体器官中，用^ 1h -探测^<13>C NMR法无创追踪。葡萄糖在0.5小时内达到最高水平，注射bolas后迅速下降。然而，葡萄糖代谢反应产生的谷氨酰胺/谷氨酸在1小时内达到最高水平，并在此高水平保持约2小时以上。在这一稳定时期，化学位移成像技术被应用于研究这些代谢物在大脑中的分布。研制了一种可见分光光度计，用于测定活体动物的血氧水平。为了提高血氧水平检测的灵敏度，我们采用了含氧和脱氧血红蛋白的soret波段波长和这两个吸收点的等吸点。光度计的另一个特点是该仪器有独立的两个探测器，可以同时测量大鼠脑的左右半球。采用近红外光谱法监测无创血氧水平。为此，在Chance博士的实验室中开发了具有750和830nm光源和13通道检测器的分光光度计。用该仪器在30秒左右的时间内对大鼠脑缺血时的脱氧情况和血容量进行了跟踪，并绘制了脑缺血图。部分配体no -血红蛋白在氧结合中具有独特的性质。通过光谱和氧结合研究发现其为典型的t型结构。因此，这种类型的血红蛋白可以作为一个有效的氧气释放在需要氧气的组织或器官在生命系统。

1. Fast scanning echo planar imaging (EPI) approach in MRI was incorporated into newly developed highly sensitive ^1H-detected in vivo ^<13>C NMR spectroscopy, which was developed in our laboratory by the integration of hetero nuclear multiple quantum coherence (HMQC) technique and non-invasive localization method.2. Injected glucose labeled by ^<13>C into living organs was traced non-invasively by ^1H-detected ^<13>C NMR method. Glucose reached to the highest level in 0.5 hours and decreased rapidly after a bolas injection. However, glutamine/glutamate derived by the metabolic reaction of the glucose reached to the highest level in 1 hour and stayed at this high level for approximately two more hours. In this stable period a chemical shift imaging technique was applied to investigate the distribution of these metabolites in brain.3. A visible spectrophotometer has been developed to investigate blood oxygen level in living animals. In order to gain sensitivity for blood-oxygen level detection, we employed a Soret-band wavelengths of oxy and deoxy hemoglobin and isosbestic point of these two absorbances. Another feature of the photometer is that this instrument has independent two detectors, which can simultaneously measure right and left hemisphere in rat brain.4. Near infra red spectroscopy was employed to monitor non-invasively oxygen level in blood. For this a spectrophotometer having 750 and 830nm light sources and 13-channel detector was developed in Dr. Chance's laboratory. With this instrument deoxygenation and blood volume were traced during brain ischemia in rat and their maps were also constructed in approximately 30 seconds.5. A partially liganded NO-hemoglobin was elucidated to bear unique nature in oxygen binding. It was found to be in typical T-structure by spectroscopic and oxygen binding studies. Therefore, this type of hemoglobin may be utilized as an effective oxygen release at the oxygen-demanded tissues or organs in-living system.