Abstract
We have been developing the methods of measuring in vivo brain metabolism using 2T 13C NMR (nuclear magnetic resonance) spectroscopy (13C-MRS) research system. These methods make it possible to measure the synthesis rates of metabolites such as glutamate in the hemispheres simultaneously by using the 13C, stable isotope, as a tracer. In this study, we have used these newly developed methods to determine the rate of glutamate synthesis in the hemispheres of monkey (Macaca fascicularis crab-eating macaque) brain after transient (60 min) middle cerebral artery occlusion (MCAO). Animals had no behavioral anomaly induced by MCAO throughout this study. 13C-MRS measurements were performed for 2 hours at 1, 3, 8, 16 and 80 days after the onset of MCAO with intravenous injection of [1-113C] glucose (1 g/ kg). The amounts of 13C incorporation into glutamate in the ipsilateral region were significantly decreased at 3 and 8 days after the insult as compared with the collateral region (P < 0.05). These data may suggest that MCAO induces metabolic dysfunction involved in mitochondrial abnormality and demonstrate that 13C-MRS can provide information that is useful for assessing brain metabolism non-invasively. [Jpn J Physiol 55 Suppl:S203 (2005)]
