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EFFECTS OF EXCITATORY NEUROTRANSMITTER AMINO ACIDS ON SWELLING OF RAT BRAIN CORTICAL SLICES 1
Author(s) -
Chan Pak H.,
Fishman Robert A.,
Lee Jane L.,
Candelise Livia
Publication year - 1979
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.1471-4159.1979.tb05278.x
Subject(s) - taurine , amino acid , biochemistry , glutamate receptor , chemistry , glutamic acid , intracellular , glycine , neurotransmitter , kainic acid , aspartic acid , biology , receptor
— With the single rat brain cortical slice serving as an in vitro bio‐assay system, the effects of neurotransmitter amino acids (1 m m ) on brain swelling, water, sodium and potassium content, inulin space, and lactate production were studied. The putative dicarboxylic amino acid neurotransmitters, l ‐glutamic acid and l ‐aspartic acids, greatly increased intracellular brain swelling with increased intracellular Na + , water content and lactate production, and decreased inulin space and intracellular K + . Equimolar GABA, taurine, glycine, the putative inhibitory neurotransmitter amino acids, and equimolar α‐amino‐isobutyric acid had no effect. Brain swelling and intracellular Na + /K + ratios were greatly increased by l ‐glutamate and l ‐aspartate at a concentration of 10 m m . However, l ‐aspartate at these concentrations greatly depleted the K + content and lactate production as compared to l ‐glutamate. Further studies indicated that only the structural analogs and isomers of the dicarboxylic amino acids possessing two acidic groups and an α‐amino group had a similar effect on the induction of brain swelling. Among the analogs of glutamic acid, dl ‐homocysteic acid and kainic acid had a greater effect on brain swelling, as observed from the total adenosine 5′‐triphosphate (ATP) levels and the time‐course and dose‐response. A biphasic response in lactate production was induced by dl ‐homocysteic acid and kainic acid, suggesting that these analogs had a neurotoxic effect on cellular metabolism at higher concentrations.