Characterization of separated cell types from developing rat cerebellum. Transport of [3H]GABA by preparations enriched in Purkinje cells and astrocytes.

The characteristics of [3H]GABA transport were investigated in preparations greatly enriched in different classes of cerebellar cells. In contrast to observations in situ, isolated Purkinje cells readily accumulated [3H]GABA. In comparison with astrocytes, the Vmax of the high-affinity uptake process was sixfold higher (0.31 vs. 0.05 nmol/min/10(6) cells) and the apparent Kt twofold greater (2 vs. 1 microM). In contrast to these cell types, uptake was very low in granule cell-enriched preparations. cis-1,3-aminocyclohexane carboxylic acid was a potent inhibitor of [3H]GABA uptake by the Purkinje cells and a weak blocker in astrocytes, while the converse was the case for beta-alanine. Diaminobutyric acid strongly inhibited uptake in both cell types. [3H]GABA transport was Na+ dependent in both cell classes. However, veratridine and ouabain selectively blocked [3H]GABA accumulation in the Purkinje cells, which were also more sensitive than the astrocytes to the glycolysis inhibitor, NaF. The results indicated, therefore, marked differences between Purkinje cells and astrocytes in the properties of both the [3H]GABA transport systems and the underlying metabolic processes.