The uptake of γ-aminobutyrate by organotypic cultures of chick spinal cord

Abstract

1. Explants of spinal cord from 10-day chick embryos maintained for up to 16 days in culture rapidly accumulated gamma-amino[(3)H]butyrate when incubated at 25 degrees C or 36 degrees C in a medium containing 50nm-gamma-aminobutyrate. The mechanism of the uptake process has many of the properties of an active-transport system: it is Na(+)-dependent, temperature-sensitive, inhibited by ouabain, and displays saturation kinetics. The apparent K(m) for gamma-aminobutyrate is 1.7x10(-5)m, and V(max.) is 33pmol/min per g. 2. The rate of accumulation of gamma-amino[(3)H]butyrate in cultures between the ages of 3 and 16 days was remarkably constant and was not related to the morphological maturity of the spinal-cord explants. 3. The present demonstration in spinal-cord explants of an active transport system for gamma-aminobutyrate, already established for non-cultured nervous tissue, means that nervous-tissue culture can provide a convenient model for studying uptake processes in the central nervous system.

Uptake of GABA by neuronal and nonneuronal cells in dispersed cell cultures of postnatal rat cerebellum

“…On the other hand, in a study using cultured rat C-6 glioma, ouabain had only a minimal effect on [3H]GABA uptake (Schrier and Thompson, 1974). In addition, there are a number of studies using slices, minces, or explant cultures of vertebrate CNS tissue containing neurons and glial cells which indicate that ouabain treatment resulted in only 26-66% inhibition of ["H]GABA uptake, similar to the 54% inhibition seen in the K24 cultures (Tunnicliff, Cho, Blackwell, Martin, and Wood, 1973;Cho, Tunnicliff, and Martin, 1974;Davidoff and Adair, 1974;Kelly, Luttges, Johnson, and Grove, 1974). Also, fractions of CNS tissue enriched in neuronal membranes showed an increased sensitivity to ouabain inhibition of ["HIGABA uptake (Henn and Hamberger, 1971;Snodgrass, Hedley-White, and Lorenzo, 1973).…”