High-affinity uptake of gamma-[3H]aminobutyric acid by isolated mouse oligodendrocytes in culture.

Oligodendrocytes were isolated from mixed glial cultures of neonatal mouse forebrain and further grown in serum-free hormone supplemented culture medium. Cell populations were identified by indirect immunofluorescence using a range of specific antibodies, revealing a predominantly immature population of oligodendrocytes, the majority expressing the myelin glycolipids galactocerebroside and sulfatide on their plasma membrane. Astroglial contamination was found to be minimal. Simultaneous autoradiography and immunofluorescence demonstrated the presence of a transport system for the major inhibitory neurotransmitter GABA in the oligodendrocytes. The transport system was found to be energy, sodium and temperature dependent. Kinetic analysis revealed a high affinity system, with a Km of 6.27 microM and Vmax of 0.714 nmol/min/mg protein, which is comparable to that found previously for CNS neurons and astrocytes.