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On the origin of ex...
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Herrera-Marschitz, M
(author)
On the origin of extracellular glutamate levels monitored in the basal ganglia of the rat by in vivo microdialysis
- Article/chapterEnglish1996
Publisher, publication year, extent ...
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2002-11-23
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Wiley,1996
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printrdacarrier
Numbers
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LIBRIS-ID:oai:DiVA.org:uu-50723
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https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-50723URI
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https://doi.org/10.1046/j.1471-4159.1996.66041726.xDOI
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http://kipublications.ki.se/Default.aspx?queryparsed=id:1945810URI
Supplementary language notes
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Language:English
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Summary in:English
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Subject category:ref swepub-contenttype
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Subject category:art swepub-publicationtype
Notes
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Several putative neurotransmitters and metabolites were monitored simultaneously in the extracellular space of neostriatum, substantia nigra, and cortex and in subcutaneous tissue of the rat by in vivo microdialysis. Glutamate (Glu) and aspartate (Asp) were at submicromolar and gamma-aminobutyric acid (GABA) was at nanomolar concentrations in all brain regions. The highest concentration of dopamine (DA) was in the neostriatum. Dynorphin B (Dyn B) was in the picomolar range in all brain regions. Although no GABA, DA, or Dyn B could be detected in subcutaneous tissue, Glu and Asp levels were 5 and approximately 5 and approximately 0.4 microM, respectively. Lactate and pyruvate concentrations were approximately 200 and approximately 10 microM in all regions. The following criteria were applied to ascertain the neuronal origin of substances quantified by microdialysis: sensitivity to (a) K+ depolarization, (b) Na+ channel blockade, (c) removal of extracellular Ca2+, and (d) depletion of presynaptic vesicles by local administration of alpha-latrotoxin. DA, Dyn B, and GABA largely satisfied all these criteria. In contrast, Glu and Asp levels were not greatly affected by K+ depolarization and were increased by perfusing with tetrodotoxin or with Ca2+-free medium, arguing against a neuronal origin. However, Glu and Asp, as well as DA and GABA, levels were decreased under both basal and K+-depolarizing conditions by alpha-latrotoxin. Because the effect of K+ depolarization on Glu and Asp could be masked by reuptake into nerve terminals and glial cells, the reuptake blocker dihydrokainic acid (DHKA) or L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC) was included in the microdialysis perfusion medium. The effect of K+ depolarization on Glu and Asp levels was increased by DHKA, but GABA levels were also affected. In contrast, PDC increased only Glu levels. It is concluded that there is pool of releasable Glu and Asp in the rat brain. However, extracellular levels of amino acids monitored by in vivo microdialysis reflect the balance between neuronal release and reuptake into surrounding nerve terminals and glial elements.
Subject headings and genre
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microdialysis
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excitatory amino acids
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monoamines
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neuropeptides
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rat
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MEDICINE
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MEDICIN
Added entries (persons, corporate bodies, meetings, titles ...)
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You, Z-B
(author)
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Goiny, MKarolinska Institutet
(author)
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Meana, J J
(author)
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Silveira, R
(author)
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Godukhin, O V
(author)
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Chen, Y
(author)
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Espinoza, S
(author)
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Pettersson, E
(author)
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Loidl, C F
(author)
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Lubec, G
(author)
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Andersson, K
(author)
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Nylander, IngridClinical Neuroscience, Karolinska Institute, Stockholm, Sweden(Swepub:uu)iny08577
(author)
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Terenius, LKarolinska Institutet
(author)
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Ungerstedt, UKarolinska Institutet
(author)
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HerreraMarschitz, M
(author)
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Karolinska InstitutetClinical Neuroscience, Karolinska Institute, Stockholm, Sweden
(creator_code:org_t)
Related titles
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In:Journal of Neurochemistry: Wiley66:4, s. 1726-17350022-30421471-4159
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Herrera-Marschit ...
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You, Z-B
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Goiny, M
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Meana, J J
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Silveira, R
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Godukhin, O V
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Chen, Y
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Espinoza, S
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Pettersson, E
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Loidl, C F
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Lubec, G
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Andersson, K
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Nylander, Ingrid
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Terenius, L
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Ungerstedt, U
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HerreraMarschitz ...
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