Autoradiographic studies on the cellular localization of GABA and beta-alanine uptake by neurones and glia in tissue culture.
Nervous tissue cultures have proved to be an excellent tool for investigating the cellular localization of the uptake of transmitter substances using autoradiography. The uptake of [3H]GABA and [3H]beta-alanine was studied in cultures of cerebellum, brain stem, spinal cord and dorsal root ganglia (DRG) of the rat. In cultures of brain stem and spinal cord, [3H]GABA was taken up by a great number of neurones and by almost all glial cells, suggesting that glial elements might also be involved in the inactivation of this amino acid. In cerebellar cultures, [3H]GABA was accumulated by many interneurones, by Purkinje cells and by a great number of glial cells. The finding that cultured Purkinje cells accumulated [3H]GABA contrasts with observations made in the cerebellum in vivo or in slices where no labelling of Purkinje cells could be demonstrated. Since GABA is taken up to a great extent by Bergman glia which tightly surround Purkinje cells in vivo, it has been suggested that the barrier formed by these glial cells prevents the uptake of the amino acid into Purkinje cells. In cultured cerebellum this glial barrier might be disrupted or absent and therefore Purkinje cells are able to accumulate [3H]GABA. A similar glial barrier preventing the uptake of [3H]GABA might also exist in DRG, where neurones that were completely surrounded by satellite glial cells did not take up the amino acid, whereas isolated neurones that were deprived of their glial envelopments became intensely labelled. After incubation with [3H]beta-alanine, it was observed that only glial cells were labelled in cerebellar and DRG cultures, whereas in spinal cord and brain stem both neurones and glial cells took up the amino acid providing further evidence that beta-alanine might act as a transmitter substance in these two regions.
D000409:Alanine / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D001692:Biological Transport; D001921:Brain / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009924:Organ Culture Techniques; D051381:Rats; D013116:Spinal Cord / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid; D000409:Alanine