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Sodium dependence of GABA transport in rat hypothalamic synaptosomes
Author(s) -
Wheeler D. D.
Publication year - 1980
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490050409
Subject(s) - hypothalamus , sodium , chemistry , endocrinology , medicine , synaptosome , cortex (anatomy) , aminobutyric acid , biophysics , neuroscience , biology , biochemistry , central nervous system , receptor , organic chemistry
The sodium dependence of γ‐aminobutyric acid (GABA) uptake has been studied in rat hypothalamic synaptosomes, and the results compared to previous studies in cortical synaptosomes. Initial velocity of GABA uptake was measured as a function of both GABA and sodium concentration, and these data were fitted to the rate equation for each of several plausible models. The minimal best‐fit model was found to be identical to that for cortical synaptosomes. However, the constants which quantitate the model were found to differ for hypothalamus and cortex. As a result, uptake at any combination of [Na] and [G] in hypothalamic synaptosomes is approximately double that in cortical synaptosomes. The rate equation for the minimal best‐fit model was utilized to define and compute certain parameters which are useful in comparing transport mechanisms (Vmax, Va, Kt, Jm, and K Na ). In all cases, differences were found between hypothalamus and cortex.