.png){kind=icon}
.png){kind=icon}
Return
Quantitative Assessment of Neurometabolism by Deuterium and Proton NMR Spectroscopy Using [6; 6′-2H2]Glucose
.png){kind=icon}
PRE
AI
A
R
A
DOI：10.1021/acschemneuro.6c00030.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Neurometabolic analysis is routinely performed using 13C NMR/MRS in conjunction with the administration of 13C-labeled tracers. Despite its widespread use, the low sensitivity of 13C NMR necessitates long acquisition times. To address this limitation, the present study introduces an indirect approach that uses a single 1H NMR acquisition to measure deuterium labeling by exploiting labeling at specific sites, thereby providing a novel and more efficient strategy for assessing neurometabolism. In this study, male SD rats were infused with [6,6’-2H2]glucose for 10–90 min, and the 2H labeling of cortical metabolites was measured ex vivo using 2H NMR spectroscopy. After 90 min of [6,6′-2H2]glucose infusion, resonances corresponding to [3-2H2]lactate, [4-2Hx]glutamate, [4-2Hx]glutamine, and [3-2H]aspartate (∼2.60 ppm) were detected. In contrast, signals corresponding to [2-2H]aspartate (∼3.90 ppm), [2-2H]glutamate (∼3.76 ppm), and [3-2H]glutamate (∼2.09 ppm) were not detected, even after prolonged infusion, suggesting complete loss of the 2H label during the second turn of the tricarboxylic acid cycle. The cerebral metabolic rate of glucose oxidation, estimated by fitting an exponentially saturating curve to the pooled labeling of [4-2Hx]glutamate, [4-2Hx]glutamine, and [3-2H]aspartate, was 0.389 ± 0.031 μmol/g/min. The [4-2Hx]glutamate levels were also derived by subtracting the [4-1H2]glutamate resonance intensity from total [4-1H2]glutamate intensity estimated using the [3-1H2]glutamate intensity in unedited 1H NMR spectra. The concentrations of [4-2Hx]glutamate determined from 1H NMR spectra were comparable to those determined from 2H NMR. Moreover, when applied to 5xFAD mice (2.53 ± 0.43 μmol/g, n = 7), a model of Alzheimer’s disease, this indirect approach revealed significantly reduced (p = 0.028) [4-2Hx]glutamate levels compared with controls (2.99 ± 0.15 μmol/g, n = 7). This decrease was comparable to that observed with the direct 2H NMR measurements and was consistent with findings from 13C tracer-based studies.
Keywords:
Carbohydrates
Central nervous system
Metabolism
Nuclear magnetic resonance spectroscopy
Rodent models
glutamate
indirect detection
cerebral metabolic rate of glucose oxidation (CMRGlc(Ox))
Alzheimer’s disease
Journal
IF:
3.9
Papers:
4.5K
Citations:
1.3W
Organization
Cited Papers