Accession Number : ADA304187

Title :   The Cerebral Metabolism of Amino Acids and Related Metabolites as Studies by 13C and 14C Labelling.

Corporate Author : NORWEGIAN DEFENCE RESEARCH ESTABLISHMENT KJELLER

Personal Author(s) : Hassel, Bjernar

PDF Url : ADA304187

Report Date : 22 NOV 1995

Pagination or Media Count : 103

Abstract : The present investigations show the feasibility of analyzing the cerebral metabolism of amino acids and related metabolites by 3C-and 14C-labelling using labelled acetate and glucose as markers for glial and neuronal metabolism, respectively. Using (13C) acetate, it was shown that glial cells export 60% of their TCA cycle intermediates, mostly as glutamine, and that this glutamine is used by neurons partly as an energy reserve, partly it is converted directly to glutamate and GABA. Using (13Clglucose, the glial process of pyruvate carboxylation was shown to compensate fully for the loss of glutamine. The mechanism of action of two neurotoxins, fluorocitrate and 3-nitropropionate, was elucidated. The latter toxin was shown to inhibit the TCA cycle of GABAergic neurons selectively. Formation of pyruvate and lactate from glial TCA cycle intermediates was demonstrated in vivo. This pathway may be important for the glial inactivation of transmitter glutamate and GABA. The results illustrate glia- neuronal interactions, and they suggest the applicability of 13CNMR spectroscopy to the detailed study of the cerebral metabolism of amino acids in the intact, unanesthetized human brain.

Descriptors :   *NUCLEAR MAGNETIC RESONANCE, *SPECTROSCOPY, *METABOLISM, *AMINO ACIDS, BRAIN, HUMANS, INTERACTIONS, GLUTAMIC ACID, TRANSMITTERS, NERVE CELLS, MARKERS, LOSSES, SALTS, IN VIVO ANALYSIS, TOXINS AND ANTITOXINS, ACETATES, METABOLITES, GLUCOSE, LABELED SUBSTANCES, CEREBRUM, LACTATES, NEUROTOXINS, GLUTAMINE, PYRUVATES.

Subject Categories : Biochemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE