gamma-Aminobutyric acid uptake by rat kidney brush-border membrane vesicles

Brush-border membrane vesicles (BBMV) from rat kidney cortex possessed two uptake systems for gamma-aminobutyric acid (GABA), a high affinity system (Km = 10.9 microM) and a low affinity system (Km = 1203 microM). Both uptake systems were inhibited by p-hydroxymercuribenzoic acid and ouabain, and by the action of neuraminidase, whereas the GABA analogs nipecotic acid, beta-alanine, 2,4-diaminobutyric acid and 4,5,6,7-tetrahydroisoxazolo-4,5 c]-pyridin-3-ol had no effect on the GABA uptake activity. The BBMV uptake systems were clearly different from the GABA transport systems present in brain tissue.