Moreno A, Ross B D, Blüml S
Huntington Medical Research Institutes, Pasadena, California 91105, USA.
J Neurochem. 2001 Apr;77(1):347-50. doi: 10.1046/j.1471-4159.2001.t01-1-00282.x.
A non-invasive (13)C magnetic resonance spectroscopy (MRS) technique is described for the determination of the N-acetyl-L-aspartate (NAA) synthesis rate, V(NAA), in the human brain in vivo. In controls, the mean V(NAA) was 9.2 +/- 3.9 nmol/min/g. In Canavan disease, where [NAA] is increased (p < 0.001) and [aspartate] is deceased (p < 0.001), V(NAA) was significantly reduced to 3.6 +/- 0.1 nmol/min/g (p < 0.001). These rates are in close agreement with the activity of the biosynthetic enzyme measured in vitro in animals, and with the rate of urinary excretion of NAA in human subjects with Canavan disease. The present result is consistent with the regulation of NAA synthesis by the activity of a single enzyme, L-aspartate-N-acetyltransferase, in vivo, and with its control in Canavan disease by limited substrate supply and/or product inhibition. The (13)C MRS technique provides the means for further determination of abnormal rates of neuronal NAA synthesis among neurological disorders in which low cerebral [NAA] has been identified.
描述了一种用于测定活体人脑中N-乙酰-L-天冬氨酸（NAA）合成速率V（NAA）的非侵入性碳-13磁共振波谱（MRS）技术。在对照组中，V（NAA）的平均值为9.2±3.9 nmol/（min·g）。在Canavan病中，NAA含量升高（p<0.001），天冬氨酸含量降低（p<0.001），V（NAA）显著降低至3.6±0.1 nmol/（min·g）（p<0.001）。这些速率与在动物体外测量的生物合成酶活性以及Canavan病患者尿中NAA的排泄速率密切一致。目前的结果与体内单一酶L-天冬氨酸-N-乙酰转移酶的活性对NAA合成的调节以及Canavan病中通过有限的底物供应和/或产物抑制对其进行的控制相一致。碳-13 MRS技术为进一步测定已确定脑内NAA含量低的神经系统疾病中神经元NAA合成的异常速率提供了手段。
