Characteristics of dopamine and GABA transport in primary cultures of astroglial cells

Primary astroglial cultures were grown from newborn rat cerebral hemispheres. Cultures, aged 7 and 14 days, were analysed with respect to their capacity to accumulate radioactive GABA and dopamine. Concentrative high-affinity uptake, showing Na+-dependence was observed for GABA where Km and Vmax were not significantly altered with age of the culture. No Na+-dependent high-affinity transport of dopamine was observed. The addition of 0.1 mM dibutyryl-cyclic-3'-5'-adenosinemonophosphate (dB-cAMP) after removal of fetal calf-serum reduced the Vmax as well as the Km of 3H-GABA uptake. The ionic dependence of 3H-GABA and 3H-dopamine was not significantly altered following this treatment. The results are difficult to interpret in terms of a potentiated differentiation of the cells.