Koller K J, Zaczek R, Coyle J T
J Neurochem. 1984 Oct;43(4):1136-42. doi: 10.1111/j.1471-4159.1984.tb12854.x.
An isocratic HPLC method to measure endogenous N-acetyl-aspartyl-glutamate (NAAG) and N-acetyl-aspartate (NAA) is described. After removal of primary amines by passage of tissue extracts over AG-50 resin, the eluate was subject to HPLC anion-exchange analysis and eluted with phosphate buffer with absorbance monitored at 214 nm. The retention time for NAA was 5.6 min and for NAAG 11.4 min with a limit sensitivity of 0.1 nmol. The levels of NAA and NAAG were measured in 16 regions of rat brain and in heart and liver. NAAG was undetectable in heart and liver and exhibited 10-fold variation in concentration among brain regions; the highest levels were found in spinal cord. In contrast, low concentrations of NAA were detectable in heart and liver, and the regional distribution of NAA in brain varied only twofold. The regional distribution of NAA and NAAG correlated poorly. To assess the neuronal localization of these two compounds, the effects of selective brain lesions on their levels were examined. Decortication caused a 28% decrease in NAAG levels in the ipsilateral striatum while NAA decreased 38%. Kainate lesion of the striatum resulted in a 31% decrease in NAAG in the ipsilateral striatum, whereas NAA fell by 58%. Kainate lesion of the hippocampus resulted in significant decrements in NAAG and NAA in the hippocampus and septum. Transection of the spinal cord at midthorax resulted in a 51% decrease in NAAG levels immediately caudal and a 40% decrease immediately rostral to the lesion; however, NAA decreased only 30% in these areas. These results are consistent with a neuronal localization of NAAG in brain.(ABSTRACT TRUNCATED AT 250 WORDS)
本文描述了一种用于测定内源性N-乙酰天门冬氨酰谷氨酸（NAAG）和N-乙酰天门冬氨酸（NAA）的等度高效液相色谱法。通过将组织提取物通过AG-50树脂去除伯胺后，将洗脱液进行高效液相色谱阴离子交换分析，并用磷酸盐缓冲液洗脱，在214nm处监测吸光度。NAA的保留时间为5.6分钟，NAAG为11.4分钟，检测限为0.1nmol。在大鼠脑的16个区域以及心脏和肝脏中测量了NAA和NAAG的水平。在心脏和肝脏中未检测到NAAG，其在脑区域中的浓度变化有10倍差异；最高水平出现在脊髓中。相比之下，在心脏和肝脏中可检测到低浓度的NAA，且NAA在脑中的区域分布仅相差两倍。NAA和NAAG的区域分布相关性较差。为了评估这两种化合物的神经元定位，研究了选择性脑损伤对其水平的影响。去皮质导致同侧纹状体中NAAG水平降低28%，而NAA降低38%。纹状体的海人酸损伤导致同侧纹状体中NAAG降低31%，而NAA下降58%。海马的海人酸损伤导致海马和隔区中NAAG和NAA显著降低。在胸中部横断脊髓导致损伤部位尾侧立即出现NAAG水平降低51%，损伤部位头侧立即降低40%；然而，这些区域中NAA仅降低30%。这些结果与NAAG在脑中的神经元定位一致。（摘要截短至250字）
