Positive correlation between rat brain glutamate concentrations and mitochondrial 2-oxoglutarate dehydrogenase activityстатья
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Дата последнего поиска статьи во внешних источниках: 29 ноября 2023 г.
Аннотация:Highlights•Brain glutamate positively correlates with activity of 2–oxoglutarate dehydrogenase.•The correlation is stronger in the brain cortex vs cerebellum.•Mitochondrial impairment decreases the correlation coefficient and p value.•The decrease reveals perturbed glutamate metabolism better than the glutamate mean.•Glutamate correlates to GABA in the brain cortex, but not in the cerebellum.AbstractGlutamate is a key metabolite and major excitatory neurotransmitter, degraded through transformation to 2-oxoglutarate which is further catabolized by 2-oxoglutarate dehydrogenase complex (OGDHC). Both the glutamate excitotoxicity and impaired OGDHC activity are hallmarks of neurodegeneration. This work quantifies a relationship between the brain OGDHC activity and glutamate levels, assessing its diagnostic value to characterize (patho)physiology. A moderate to strong positive correlation of the two parameters determined under varied physiological settings (brain regions, seasons, gender, pregnancy, rat line), is revealed. Mitochondrial impairment (OGDHC inhibition or acute hypobaric hypoxia) decreases the interdependence, even when the parameter means do not change significantly. Compared to the cortex, the cerebellum exhibits a lower inter-individual glutamate variation and a weaker glutamate-OGDHC interdependence. Specific metabolism of the brain regions is also characterized by a positive correlation between glutamate and γ-aminobutyric acid (GABA) concentrations in the cortex but not in the cerebellum. In contrast, a strong positive correlation between glutamate and glutamine is present in both the cortex and cerebellum. The differences in metabolic correlations are in line with transcriptomics data which suggest that glutamate distribution between competitive pathways contributes to the brain-region-specific features of the interdependences of glutamate and OGDHC or GABA.KeywordsCerebellum; Cortex; Correlated changes; Glutamate; 2-oxoglutarate dehydrogenase; Tricarboxylic acid cycle