Action of GABA and glycine on the membrane potential of culture astrocytes and the extracellular concentration.

The depolarization of cultured astrocytes by GABA and glycine correlates in amplitude and time course with the increase of the extracellular K+ -concentration during perfusion with these amino acids. It is suggested that the glial depolarization is caused by an efflux of K+ from neighbouring neurones activated by the amino acid transmitters.