Stimulus-Coupled Secretion of γ-Aminobutyric Acid from Rat Brain Synaptosomes

Science  17 Aug 1973:
Vol. 181, Issue 4100, pp. 676-678
DOI: 10.1126/science.181.4100.676


Synaptosomes treated with radioactive γ-aminobutyric acid can be stimulated to release this substance. The release is maximal within 40 seconds after stimulation and is dependent on calcium. Magnesium and manganese ions, known to block stimulus-secretion coupling processes, depress calcium-dependent release. This release is specific to synaptosomes because microsomal or myelin fractions do not release accumulated γ-aminobutyric acid. The data illustrate a simple in vitro system suitable for analysis of secretion of γ-aminobutyric acid in brain and in addition describe several new aspects of uptake and secretion of this compound at brain nerve endings.