Sodium-dependent Metabolism and Transport of γ-Aminobutyric Acid in Subcellular Particles from Brain
The properties of γ-aminobutyric acid (γABA) are of great interest in the biochemistry and physiology of the vertebrate central nervous system . γABA is found to associate with mitochondria, microsomes and nerve ending particles, all of which can be sedimented from mouse brain homogenates in 0.25 M sucrose by centrifugation between 1,500 and 15,000 × g. When a pellet is resuspended in 0.2 M NaCl (buffered at pH 7.3) and incubated at 0–4° C in the presence of 2-14C-γABA, a rapid accumulation of radioactivity in the particle occurs. This accumulation is dependent on the presence of Na+ ions. A series of studies, reviewed in the preceding paper , has led to the postulation of an equilibrating carrier mechanism for the uptake of γABA at 0°C. The Na-dependence of this mechanism lies in a Na+ ion requirement for the carrier to bind γABA.
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