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In Vivo Release of Endogenous Amino Acids from the Rat Striatum: Further Evidence for a Role of Glutamate and Aspartate in Corticostriatal Neurotransmission
Author(s) -
Girault Jean Antoine,
Barbeito Luis,
Spampinato Umberto,
Gozlan Henri,
Glowinski Jacques,
Besson MarieJo
Publication year - 1986
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1986.tb02836.x
Subject(s) - glutamate receptor , taurine , glutamine , tetrodotoxin , tyrosine , striatum , endogeny , medicine , chemistry , endocrinology , amino acid , glutamic acid , biology , biochemistry , dopamine , receptor
By means of the push‐pull cannula method, the outflow of endogenous amino acids was studied in the striatum of halothane‐anesthetized rats. Addition of K + ions (30 m M for 4 min) to the superfusion fluid increased the release of aspartate (+116%), glutamate (+ 217%), taurine ( + 109 % ), and γ‐aminobutyric acid (GABA) (−429%) whereas a prolonged decrease in the outflow of glutamine ( −28% ) and a delayed reduction in the efflux of tyrosine (−25%) were observed. In the absence of Ca 2‐ , the K + ‐induced release of aspartate, glutamate, and GABA was blocked whereas the K + ‐induced release of taurine was still present. Under these conditions, the decrease in glutamine efflux was reduced and that of tyrosine was abolished. Local application of tetrodotoxin (5 μ M ) decreased only the outflow of glutamate (‐25%). One week following lesion of the ipsilateral sensorimotor cortex the spontaneous outflow of glutamine and of tyrosine was enhanced. Despite the lack of change in their spontaneous outflow, the K + ‐evoked release of aspartate and glutamate was less pronounced in lesioned than in control animals, whereas the K + ‐evoked changes in GABA and glutamine efflux were not modified. Our data indicate that the push‐pull cannula method is a reliable approach for the study of the in vivo release of endogenous amino acids. In addition, they provide further evidence for a role for glutamate and aspartate as neuro‐transmitters of corticostriatal neurons.