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[U‐ 13 C]aspartate metabolism in cultured cortical astrocytes and cerebellar granule neurons studied by NMR spectroscopy
Author(s) -
Johanne Bakken Inger,
White Linda R.,
Aasly Jan,
Unsgård Geirmund,
Sonnewald Ursula
Publication year - 1998
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/(sici)1098-1136(199807)23:3<271::aid-glia9>3.0.co;2-7
Subject(s) - glycolysis , biology , glutamine , granule (geology) , glutamate receptor , biochemistry , metabolism , citric acid cycle , astrocyte , neuroglia , granule cell , citrate synthase , cerebellum , neuroscience , amino acid , central nervous system , enzyme , receptor , paleontology , dentate gyrus
The metabolism of [U‐ 13 C]aspartate was studied in cultured cortical astrocytes and cerebellar granule neurons in the presence of glucose and during inhibition of glycolysis. Redissolved, lyophilized cell extracts and incubation media were analyzed by 13 C nuclear magnetic resonance spectroscopy for the determination of metabolites labeled from aspartate. Uniformly labeled lactate was prominent in control media of astrocytes and cerebellar granule neurons. In both cell types, aspartate entered the tricarboxylic acid (TCA) cycle, as shown by labeling patterns in glutamate and, in astrocytes, in glutamine. From the complex labeling patterns in aspartate in astrocytic perchloric acid extracts it was clear that acetylcoenzyme A (acetyl‐CoA) derived from aspartate via oxaloacetate and pyruvate could enter the TCA cycle. Such “recycling,” however, could not be detected in cerebellar granule neurons. Inhibition of glycolysis reduced aspartate uptake and metabolism in both cell types. Most notably, lactate derived from aspartate showed a large reduction, and in astrocytes, incorporation of labeled acetyl‐CoA into the TCA cycle was significantly reduced. Thus, astrocytes and cerebellar granule neurons differ in their handling of aspartate. Furthermore, inhibition of glycolysis clearly affected aspartate metabolism by such cells. GLIA 23:271–277, 1998. © 1998 Wiley‐Liss, Inc.