Figure 4.

Desensitization properties and case-dependent modulation by CTZ and PEPA of glutamate-evoked currents in acutely isolated human astrocytes. A, Fast application of glutamate (1 mm) elicited inward currents in astrocytes from AHS and lesion specimens. The glutamate responses desensitized rapidly and almost completely, with a monoexponential current decay. Time constants of current desensitization were as indicated. B, C, After glutamate (1 mm) application, the cells were exposed to PEPA (50 μm; 30 sec), and then glutamate and PEPA were co-applied again. After washout, the same cell was incubated in CTZ (100 μm; 30 sec), and then glutamate was applied. CTZ had a larger effect on the astrocyte from an AHS specimen (B), whereas PEPA preferentially enhanced the steady-state response of the lesion cell (C). Holding potential was -70 mV.