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SUBCELLULAR DISTRIBUTION OF ENDOGENOUS AND [ 3 H] γ‐AMINOBUTYRIC ACID IN RAT CEREBRAL CORTEX
Author(s) -
Neal M. J.,
Iversen L. L.
Publication year - 1969
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.1471-4159.1969.tb05972.x
Subject(s) - endogeny , cerebral cortex , aminobutyric acid , gamma aminobutyric acid , glutamate decarboxylase , glutamate receptor , biochemistry , incubation , aminooxyacetic acid , differential centrifugation , cell fractionation , chemistry , enzyme , biology , endocrinology , receptor
Abstract— Slices of rat cerebral cortex were labelled by incubation with [ 3 H]γ‐aminobutyric acid (GABA) and homogenized in isotonic sucrose. The subcellular distributions of endogenous GAB A, [ 3 H]GABA and glutamate decarboxylase (GAD) were studied by density gradient centrifugation. The subcellular distributions of the labelled and endogenous amino acid were remarkably similar, indicating that [ 3 H]GABA is taken up into the endogenous GABA pool. About 40 per cent of both endogenous and [ 3 H]GABA were recovered in particles which were tentatively identified as synaptosomes from their equilibrium density and sensitivity to osmotic shock. In slices labelled with [ 3 H]GABA and [ 14 C]α‐aminoisobutyric (AIB) acid, significantly more [ 3 H]GABA was recovered in paniculate fractions than [ 14 C]AIB. About 80 per cent of the enzyme GAD was also recovered in the same particle fractions which contained [ 3 H]GABA and endogenous GABA. Evidence is presented which suggests that a loss of particle‐bound GABA occurs during subcellular fractionation procedures.