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In Vitro Release of Endogenous Amino Acids from Granule Cell‐, Stellate Cell‐, and Climbing Fiber‐Deficient Cerebella
Author(s) -
Flint R. S.,
Rea M. A.,
McBride W. J.
Publication year - 1981
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.1471-4159.1981.tb06311.x
Subject(s) - taurine , glutamate receptor , alanine , granule cell , granule (geology) , cerebellum , hepatic stellate cell , biology , glycine , biochemistry , biophysics , amino acid , chemistry , endocrinology , central nervous system , receptor , paleontology , dentate gyrus
The K + ‐stimulated, Ca 2+ ‐dependent release of glutamate, aspartate, ‐ γ ‐aminobutyric acid (GABA), alanine, taurine, and glycine was measured in slices of cerebella obtained from control, and granule cell‐, granule cell plus stellate cell‐, or climbing fiber‐deficient cerebella of the rat. The 55 m m ‐K + ‐stimulated release of glutamate and GABA was 10‐fold greater in the presence of Ca 2+ than in its absence. The stimulated release of aspartate was 4‐fold higher when Ca 2+ was present in the bathing media, while the value for alanine was twice as high as the amount obtained in the absence of Ca 2+ . There was no stimulated release of either taurine or glycine from the cerebellar slices. Increasing the Mg 2+ concentration to 16 HIM inhibited the K + ‐stimulated, Ca 2+ ‐dependent release of glutamate, GABA, aspartate, and alanine 85% or more. The K + ‐stimulated, Ca 2+ dependent release of glutamate, aspartate, and alanine from x‐irradiated cerebella deficient in granule cells was reduced to 50–57% of control value. Additional x‐irradiation treatment, which further reduced the cerebellar granule cell population and also prevented the acquisition of stellate cells, decreased the release of glutamate by 77%, aspartate by 66%, alanine by 91%, and, in addition, decreased the release of GABA by 55%. The K + ‐stimulated, Ca 2+ ‐dependent release of glutamate, aspartate, GABA, and alanine was not changed in climbing fiber‐deficient cerebella obtained from 3‐acetylpyridine‐treated rats. The data support a transmitter role for GABA and glutamate in the cerebellum, but do not support a similar function for either taurine or glycine. The data also suggest that alanine and aspartate may be co‐released along with glutamate from granule cells.