Accumulation of putative amino acid neurotransmitters, monoamines and D-Ala2-Met-enkephalinamide in primary astroglial cultures from various brain areas, visualized by autoradiography

Abstract

The accumulation of amino acids, monoamines and D-Ala2-Met-enkephalinamide (Enk) was visualized by autoradiography in astroglial primary cultures from different well-defined brain areas. The most prominent accumulation of grains was seen after incubating astroglial cultures from cerebral cortex, hippocampus and striatum with glutamate. Less uptake was seen in brainstem and cerebellar cultures. Similar results were found with aspartate but at a lower uptake level. The accumulation of GABA was moderate in all cultures studied. Dopamine, norepinephrine and 5-hydroxytryptamine (5-HT) showed only a slight accumulation and enkephaline did not accumulate at all. The results demonstrate that astroglial cells are not general inactivators for neurotransmitters, as monoamines are taken up only slightly and enkephalin not at all, while the cells have the capacity to accumulate at least some amino acid neurotransmitters. Furthermore, astroglial cells from different brain regions have different capacities to accumulate the various amino acid neurotransmitters supporting the view of regionally specialized astroglial cells.