Uptake and metabolism of L-(/sup 3/H)glutamate and L-(/sup 3/H)glutamine in adult rat cerebellar slices

Journal Article · Sat Oct 01 00:00:00 EDT 1983 · Neurochem. Res.; (United States)

DOI:https://doi.org/10.1007/BF00964001· OSTI ID:6541487

de Barry, J; Vincendon, G; Gombos, G

Using very low concentrations (1 mumol range) of L-2-3-(/sup 3/H)glutamate, (/sup 3/H-Glu) or L-2-3-(/sup 3/H)glutamine (/sup 3/H-Gln), the authors have previously shown by autoradiography that these amino acids were preferentially taken up in the molecular layer of the cerebellar cortex. Furthermore, the accumulation of /sup 3/H-Glu was essentially glial in these conditions. Uptake and metabolism of either (/sup 3/H-Glu) or (/sup 3/H-Gln) were studied in adult rat cerebellar slices. Both amino acids were rapidly converted into other metabolic compounds: after seven minutes of incubation in the presence of exogenous /sup 3/H-Glu, 70% of the tissue accumulated radioactivity was found to be in compounds other than glutamate. The main metabolites were Gln (42%), alpha-ketoglutarate (25%) and GABA (1,4%). In the presence of exogenous /sup 3/H-Gln the rate of metabolism was slightly slower (50% after seven minutes of incubation) and the metabolites were also Glu (29%), alpha-ketoglutarate (15%) and GABA (5%). Using depolarizing conditions (56 mM KCl) with either exogenous /sup 3/H-Glu or /sup 3/H-Gln, the radioactivity was preferentially accumulated in glutamate compared to control. From these results we conclude: i) there are two cellular compartments for the neurotransmission-glutamate-glutamine cycle; one is glial, the other neuronal; ii) these two cellular compartments contain both Gln and Glu; iii) transmitter glutamate is always in equilibrium with the so-called ''metabolic'' pool of glutamate; iv) the regulation of the glutamate-glutamine cycle occurs at least at two different levels: the uptake of glutamate and the enzymatic activity of the neuronal glutaminase.

• Research Organization: Centre de Neurochimie du CNRS, Strasbourg, France
• OSTI ID: 6541487
• Journal Information: Neurochem. Res.; (United States), Journal Name: Neurochem. Res.; (United States) Vol. 8:10; ISSN NERED
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMIDES
AMINO ACIDS
BIOLOGICAL PATHWAYS
BIOLOGY
BODY
BRAIN
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CHROMATOGRAPHY
ENZYME ACTIVITY
GLUTAMIC ACID
GLUTAMINE
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIQUID COLUMN CHROMATOGRAPHY
METABOLISM
MOLECULAR BIOLOGY
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
RADIOBIOLOGY
SEPARATION PROCESSES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE