Aspartate, glutamate and gamma-aminobutyric acid depolarize cultured astrocytes

Cultures of differentiated, glial fibrillary acidic protein-positive astrocytes from early postnatal rat cerebral hemispheres respond with depolarization of 2-36 mV to glutamate, gamma-aminobutyric acid (GABA) and aspartate but not to glycine or taurine. While GABA resulted in a transient depolarization, the effect of glutamate and aspartate persisted during the application. Since neurons were not present in these cultures a contribution of transmitter-mediated K+ release from adjacent neurons could be excluded. The depolarization triggered by these neurotransmitters is therefore an intrinsic reaction of astrocytes.