期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：11
页码：2686-2690
DOI：10.1073/pnas.68.11.2686
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Rabbit-brain fractions enriched in neuronal cell bodies and in glial cells accumulated norepinephrine, serotonin, dopamine, and {gamma}-aminobutyric acid, substances believed to serve as neurotransmitters in the central nervous system. Both neurons and glia were able to concentrate the monoamine transmitters about 4-fold from a medium containing 0.1-1 {micro}M concentrations. However, the glial-cell fraction concentrated aminobutyrate over a 100-fold from the medium, in contrast to the neuronal fraction, which concentrated this amino acid only 4-fold. The uptake of aminobutyrate by glial cells was 30-50% of that of synaptosome preparations. Its uptake in all fractions was temperature sensitive, sensitive to metabolic inhibitors, and exhibited Km values of 0.72 {micro}M for the neuronal fraction, 0.42 {micro}M for the synaptosomal fraction, and 0.27 {micro}M for the glial-cell fraction. These results are interpreted as evidence that the glial cell is involved in limiting the extracellular build-up of substances that might trigger synaptic transmission by removing any transmitters that may diffuse out of the synaptic cleft during the transmission of impulses. The possible function of the enormous ability of glia and synaptosomes to accumulate aminobutyrate is discussed in light of the actions and distribution of this substance in the central nervous system.
