J. Simon, D. Martin
Aug 1, 1973
Citations
1
Influential Citations
64
Citations
Quality indicators
Journal
Archives of biochemistry and biophysics
Abstract
Abstract l -2,4-diaminobutyric acid was studied as an inhibitor of gamma-aminobutyric acid uptake by a synaptosomal fraction isolated from rat brain. Competitive inhibition was observed during short-term exposure of the synaptosomal fraction to the inhibitor but noncompetitive inhibition was observed following prolonged exposure. Studies on the mode of action of l -2,4-diaminobutyric acid showed that the synaptosomal fraction was capable of accumulating this compound and that both the uptake and the effectiveness of the inhibitor were sodium-dependent and temperature-sensitive. In addition, the degree of inhibition of gamma-aminobutyric acid uptake was related to the amount of l -2,4-diaminobutyric acid accumulated. It is suggested that the observed noncompetitive inhibition of gamma-aminobutyric acid uptake by l -2,4-diaminobutyric acid is a result of the accumulation of the inhibitor which exerts its effect from within the synaptosomes. Raising the external concentration of gamma-aminobutyric acid to saturating levels did not completely inhibit the accumulation of l -2,4-diaminobutyric acid. Thus, the transport of l -2,4-diaminobutyric acid appears to be mediated, at least in part, by a carrier which is not involved in the transport of gamma-amiuobutyric acid.