Estimation of aspartate synthesis in GABAergic neurons in mice by 13 C NMR spectroscopy.
Aspartate synthesis in GABAergic neurons was estimated following inhibition of glutamate decarboxylase (GAD) with 3-mercaptopropionic acid (3-MPA). Mice received 3-MPA, 50 mg/kg, and [1-13C]glucose or [2-13C]acetate. Brain extracts were analyzed by 13C NMR spectroscopy. GABA synthesis was inhibited by 50%, and the synthesis of [13C]aspartate subsequently decreased by 25%. This means that 50% of cerebral aspartate is labeled from metabolites formed through the GABA shunt. A large proportion of the remaining aspartate is labeled through the TCA cycle in GABAergic neurons.
Johannessen
C U
CU
Norwegian Defence Research Establishment, PO Box 25, N-2027 Kjeller.
Qu
H
H
Sonnewald
U
U
Hassel
B
B
Fonnum
F
F
D015097:3-Mercaptopropionic Acid / Q000494:pharmacology; D000085:Acetates / Q000378:metabolism; D000596:Amino Acids / Q000096:biosynthesis; D000818:Animals; D001224:Aspartic Acid / Q000096:biosynthesis*; D002250:Carbon Radioisotopes; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D018682:GABA Agents / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis* / Q000378:metabolism
D000085:Acetates; D000596:Amino Acids; D002250:Carbon Radioisotopes; D018682:GABA Agents; D009419:Nerve Tissue Proteins; D005973:Glutamine; D001224:Aspartic Acid; D019344:Lactic Acid; D005680:gamma-Aminobutyric Acid; D015097:3-Mercaptopropionic Acid; D005968:Glutamate Decarboxylase; D005947:Glucose