Net uptake of gamma-aminobutyric acid by a high-affinity system of rat brain synaptosomes.
Rat brain synaptosomes isolated on discontinuous Ficoll gradient carry out rapid net uptake of gamma-aminobutyric acid through a high-affinity system (Km = 6.25 microM; Vmax = 1.2 nmol/min per mg of protein). The uptake of the labeled neurotransmitter is dependent on sodium concentration and is abolished by addition of 40 microM veratridine or 0.5 mM 2,4-diaminobutyric acid. Homoexchange in this preparation accounts for less than 10% of the measured uptake of gamma-amino[14C]butyric acid. It is concluded that the high-affinity transport exhibits properties characteristic of a system that is responsible for the rapid removal of gamma-aminobutyric acid from the synaptic cleft after neuronal transmission.
D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000613:Aminobutyrates; C005959:2,4-diaminobutyric acid; D005680:gamma-Aminobutyric Acid; D014701:Veratridine